#[cfg(all(    unix,    not(mio_unsupported_force_poll_poll),    not(any(target_os = "solaris", target_os = "vita"))))]use std::os::unix::io::{AsRawFd, RawFd};#[cfg(all(debug_assertions, not(target_os = "wasi")))]use std::sync::atomic::{AtomicBool, Ordering};#[cfg(all(debug_assertions, not(target_os = "wasi")))]use std::sync::Arc;use std::time::Duration;use std::{fmt, io};use crate::{event, sys, Events, Interest, Token};/// Polls for readiness events on all registered values.////// `Poll` allows a program to monitor a large number of [`event::Source`]s,/// waiting until one or more become "ready" for some class of operations; e.g./// reading and writing. An event source is considered ready if it is possible/// to immediately perform a corresponding operation; e.g. [`read`] or/// [`write`].////// To use `Poll`, an `event::Source` must first be registered with the `Poll`/// instance using the [`register`] method on its associated `Register`,/// supplying readiness interest. The readiness interest tells `Poll` which/// specific operations on the handle to monitor for readiness. A `Token` is/// also passed to the [`register`] function. When `Poll` returns a readiness/// event, it will include this token.  This associates the event with the/// event source that generated the event.////// [`event::Source`]: ./event/trait.Source.html/// [`read`]: ./net/struct.TcpStream.html#method.read/// [`write`]: ./net/struct.TcpStream.html#method.write/// [`register`]: struct.Registry.html#method.register////// # Examples////// A basic example -- establishing a `TcpStream` connection.///#[cfg_attr(all(feature = "os-poll", feature = "net"), doc = "```")]#[cfg_attr(not(all(feature = "os-poll", feature = "net")), doc = "```ignore")]/// # use std::error::Error;/// # fn main() -> Result<(), Box<dyn Error>> {/// use mio::{Events, Poll, Interest, Token};/// use mio::net::TcpStream;////// use std::net::{self, SocketAddr};////// // Bind a server socket to connect to./// let addr: SocketAddr = "127.0.0.1:0".parse()?;/// let server = net::TcpListener::bind(addr)?;////// // Construct a new `Poll` handle as well as the `Events` we'll store into/// let mut poll = Poll::new()?;/// let mut events = Events::with_capacity(1024);////// // Connect the stream/// let mut stream = TcpStream::connect(server.local_addr()?)?;////// // Register the stream with `Poll`/// poll.registry().register(&mut stream, Token(0), Interest::READABLE | Interest::WRITABLE)?;////// // Wait for the socket to become ready. This has to happens in a loop to/// // handle spurious wakeups./// loop {///     poll.poll(&mut events, None)?;//////     for event in &events {///         if event.token() == Token(0) && event.is_writable() {///             // The socket connected (probably, it could still be a spurious///             // wakeup)///             return Ok(());///         }///     }/// }/// # }/// ```////// # Portability////// Using `Poll` provides a portable interface across supported platforms as/// long as the caller takes the following into consideration:////// ### Spurious events////// [`Poll::poll`] may return readiness events even if the associated/// event source is not actually ready. Given the same code, this may/// happen more on some platforms than others. It is important to never assume/// that, just because a readiness event was received, that the associated/// operation will succeed as well.////// If operation fails with [`WouldBlock`], then the caller should not treat/// this as an error, but instead should wait until another readiness event is/// received.////// ### Draining readiness////// Once a readiness event is received, the corresponding operation must be/// performed repeatedly until it returns [`WouldBlock`]. Unless this is done,/// there is no guarantee that another readiness event will be delivered, even/// if further data is received for the event source.////// [`WouldBlock`]: std::io::ErrorKind::WouldBlock////// ### Readiness operations////// The only readiness operations that are guaranteed to be present on all/// supported platforms are [`readable`] and [`writable`]. All other readiness/// operations may have false negatives and as such should be considered/// **hints**. This means that if a socket is registered with [`readable`]/// interest and either an error or close is received, a readiness event will/// be generated for the socket, but it **may** only include `readable`/// readiness. Also note that, given the potential for spurious events,/// receiving a readiness event with `read_closed`, `write_closed`, or `error`/// doesn't actually mean that a `read` on the socket will return a result/// matching the readiness event.////// In other words, portable programs that explicitly check for [`read_closed`],/// [`write_closed`], or [`error`] readiness should be doing so as an/// **optimization** and always be able to handle an error or close situation/// when performing the actual read operation.////// [`readable`]: ./event/struct.Event.html#method.is_readable/// [`writable`]: ./event/struct.Event.html#method.is_writable/// [`error`]: ./event/struct.Event.html#method.is_error/// [`read_closed`]: ./event/struct.Event.html#method.is_read_closed/// [`write_closed`]: ./event/struct.Event.html#method.is_write_closed////// ### Registering handles////// Unless otherwise noted, it should be assumed that types implementing/// [`event::Source`] will never become ready unless they are registered with/// `Poll`.////// For example:///#[cfg_attr(all(feature = "os-poll", feature = "net"), doc = "```")]#[cfg_attr(not(all(feature = "os-poll", feature = "net")), doc = "```ignore")]/// # use std::error::Error;/// # use std::net;/// # fn main() -> Result<(), Box<dyn Error>> {/// use mio::{Poll, Interest, Token};/// use mio::net::TcpStream;/// use std::net::SocketAddr;/// use std::time::Duration;/// use std::thread;////// let address: SocketAddr = "127.0.0.1:0".parse()?;/// let listener = net::TcpListener::bind(address)?;/// let mut sock = TcpStream::connect(listener.local_addr()?)?;////// thread::sleep(Duration::from_secs(1));////// let poll = Poll::new()?;////// // The connect is not guaranteed to have started until it is registered at/// // this point/// poll.registry().register(&mut sock, Token(0), Interest::READABLE | Interest::WRITABLE)?;/// #     Ok(())/// # }/// ```////// ### Dropping `Poll`////// When the `Poll` instance is dropped it may cancel in-flight operations for/// the registered [event sources], meaning that no further events for them may/// be received. It also means operations on the registered event sources may no/// longer work. It is up to the user to keep the `Poll` instance alive while/// registered event sources are being used.////// [event sources]: ./event/trait.Source.html////// ### Accessing raw fd/socket/handle////// Mio makes it possible for many types to be converted into a raw file/// descriptor (fd, Unix), socket (Windows) or handle (Windows). This makes it/// possible to support more operations on the type than Mio supports, for/// example it makes [mio-aio] possible. However accessing the raw fd is not/// without it's pitfalls.////// Specifically performing I/O operations outside of Mio on these types (via/// the raw fd) has unspecified behaviour. It could cause no more events to be/// generated for the type even though it returned `WouldBlock` (in an operation/// directly accessing the fd). The behaviour is OS specific and Mio can only/// guarantee cross-platform behaviour if it can control the I/O.////// [mio-aio]: https://github.com/asomers/mio-aio////// *The following is **not** guaranteed, just a description of the current/// situation!* Mio is allowed to change the following without it being considered/// a breaking change, don't depend on this, it's just here to inform the user./// Currently the kqueue and epoll implementation support direct I/O operations/// on the fd without Mio's knowledge. Windows however needs **all** I/O/// operations to go through Mio otherwise it is not able to update it's/// internal state properly and won't generate events.////// ### Polling without registering event sources///////// *The following is **not** guaranteed, just a description of the current/// situation!* Mio is allowed to change the following without it being/// considered a breaking change, don't depend on this, it's just here to inform/// the user. On platforms that use epoll, kqueue or IOCP (see implementation/// notes below) polling without previously registering [event sources] will/// result in sleeping forever, only a process signal will be able to wake up/// the thread.////// On WASM/WASI this is different as it doesn't support process signals,/// furthermore the WASI specification doesn't specify a behaviour in this/// situation, thus it's up to the implementation what to do here. As an/// example, the wasmtime runtime will return `EINVAL` in this situation, but/// different runtimes may return different results. If you have further/// insights or thoughts about this situation (and/or how Mio should handle it)/// please add you comment to [pull request#1580].////// [event sources]: crate::event::Source/// [pull request#1580]: https://github.com/tokio-rs/mio/pull/1580////// # Implementation notes////// `Poll` is backed by the selector provided by the operating system.////// |      OS       |  Selector |/// |---------------|-----------|/// | Android       | [epoll]   |/// | DragonFly BSD | [kqueue]  |/// | FreeBSD       | [kqueue]  |/// | iOS           | [kqueue]  |/// | illumos       | [epoll]   |/// | Linux         | [epoll]   |/// | NetBSD        | [kqueue]  |/// | OpenBSD       | [kqueue]  |/// | Windows       | [IOCP]    |/// | macOS         | [kqueue]  |////// On all supported platforms, socket operations are handled by using the/// system selector. Platform specific extensions (e.g. [`SourceFd`]) allow/// accessing other features provided by individual system selectors. For/// example, Linux's [`signalfd`] feature can be used by registering the FD with/// `Poll` via [`SourceFd`].////// On all platforms except windows, a call to [`Poll::poll`] is mostly just a/// direct call to the system selector. However, [IOCP] uses a completion model/// instead of a readiness model. In this case, `Poll` must adapt the completion/// model Mio's API. While non-trivial, the bridge layer is still quite/// efficient. The most expensive part being calls to `read` and `write` require/// data to be copied into an intermediate buffer before it is passed to the/// kernel.////// [epoll]: https://man7.org/linux/man-pages/man7/epoll.7.html/// [kqueue]: https://www.freebsd.org/cgi/man.cgi?query=kqueue&sektion=2/// [IOCP]: https://docs.microsoft.com/en-us/windows/win32/fileio/i-o-completion-ports/// [`signalfd`]: https://man7.org/linux/man-pages/man2/signalfd.2.html/// [`SourceFd`]: unix/struct.SourceFd.html/// [`Poll::poll`]: struct.Poll.html#method.pollpub struct Poll {    registry: Registry,}/// Registers I/O resources.pub struct Registry {    selector: sys::Selector,    /// Whether this selector currently has an associated waker.    #[cfg(all(debug_assertions, not(target_os = "wasi")))]    has_waker: Arc<AtomicBool>,}impl Poll {    cfg_os_poll! {        /// Return a new `Poll` handle.        ///        /// This function will make a syscall to the operating system to create        /// the system selector. If this syscall fails, `Poll::new` will return        /// with the error.        ///        /// close-on-exec flag is set on the file descriptors used by the selector to prevent        /// leaking it to executed processes. However, on some systems such as        /// old Linux systems that don't support `epoll_create1` syscall it is done        /// non-atomically, so a separate thread executing in parallel to this        /// function may accidentally leak the file descriptor if it executes a        /// new process before this function returns.        ///        /// See [struct] level docs for more details.        ///        /// [struct]: struct.Poll.html        ///        /// # Examples        ///        /// ```        /// # use std::error::Error;        /// # fn main() -> Result<(), Box<dyn Error>> {        /// use mio::{Poll, Events};        /// use std::time::Duration;        ///        /// let mut poll = match Poll::new() {        ///     Ok(poll) => poll,        ///     Err(e) => panic!("failed to create Poll instance; err={:?}", e),        /// };        ///        /// // Create a structure to receive polled events        /// let mut events = Events::with_capacity(1024);        ///        /// // Wait for events, but none will be received because no        /// // `event::Source`s have been registered with this `Poll` instance.        /// poll.poll(&mut events, Some(Duration::from_millis(500)))?;        /// assert!(events.is_empty());        /// #     Ok(())        /// # }        /// ```        pub fn new() -> io::Result<Poll> {            sys::Selector::new().map(|selector| Poll {                registry: Registry {                    selector,                    #[cfg(all(debug_assertions, not(target_os = "wasi")))]                    has_waker: Arc::new(AtomicBool::new(false)),                },            })        }    }    /// Create a separate `Registry` which can be used to register    /// `event::Source`s.    pub fn registry(&self) -> &Registry {        &self.registry    }    /// Wait for readiness events    ///    /// Blocks the current thread and waits for readiness events for any of the    /// [`event::Source`]s that have been registered with this `Poll` instance.    /// The function will block until either at least one readiness event has    /// been received or `timeout` has elapsed. A `timeout` of `None` means that    /// `poll` will block until a readiness event has been received.    ///    /// The supplied `events` will be cleared and newly received readiness events    /// will be pushed onto the end. At most `events.capacity()` events will be    /// returned. If there are further pending readiness events, they will be    /// returned on the next call to `poll`.    ///    /// A single call to `poll` may result in multiple readiness events being    /// returned for a single event source. For example, if a TCP socket becomes    /// both readable and writable, it may be possible for a single readiness    /// event to be returned with both [`readable`] and [`writable`] readiness    /// **OR** two separate events may be returned, one with [`readable`] set    /// and one with [`writable`] set.    ///    /// Note that the `timeout` will be rounded up to the system clock    /// granularity (usually 1ms), and kernel scheduling delays mean that    /// the blocking interval may be overrun by a small amount.    ///    /// See the [struct] level documentation for a higher level discussion of    /// polling.    ///    /// [`event::Source`]: ./event/trait.Source.html    /// [`readable`]: struct.Interest.html#associatedconstant.READABLE    /// [`writable`]: struct.Interest.html#associatedconstant.WRITABLE    /// [struct]: struct.Poll.html    /// [`iter`]: ./event/struct.Events.html#method.iter    ///    /// # Notes    ///    /// This returns any errors without attempting to retry, previous versions    /// of Mio would automatically retry the poll call if it was interrupted    /// (if `EINTR` was returned).    ///    /// Currently if the `timeout` elapses without any readiness events    /// triggering this will return `Ok(())`. However we're not guaranteeing    /// this behaviour as this depends on the OS.    ///    /// # Examples    ///    /// A basic example -- establishing a `TcpStream` connection.    ///    #[cfg_attr(all(feature = "os-poll", feature = "net"), doc = "```")]    #[cfg_attr(not(all(feature = "os-poll", feature = "net")), doc = "```ignore")]    /// # use std::error::Error;    /// # fn main() -> Result<(), Box<dyn Error>> {    /// use mio::{Events, Poll, Interest, Token};    /// use mio::net::TcpStream;    ///    /// use std::net::{TcpListener, SocketAddr};    /// use std::thread;    ///    /// // Bind a server socket to connect to.    /// let addr: SocketAddr = "127.0.0.1:0".parse()?;    /// let server = TcpListener::bind(addr)?;    /// let addr = server.local_addr()?.clone();    ///    /// // Spawn a thread to accept the socket    /// thread::spawn(move || {    ///     let _ = server.accept();    /// });    ///    /// // Construct a new `Poll` handle as well as the `Events` we'll store into    /// let mut poll = Poll::new()?;    /// let mut events = Events::with_capacity(1024);    ///    /// // Connect the stream    /// let mut stream = TcpStream::connect(addr)?;    ///    /// // Register the stream with `Poll`    /// poll.registry().register(    ///     &mut stream,    ///     Token(0),    ///     Interest::READABLE | Interest::WRITABLE)?;    ///    /// // Wait for the socket to become ready. This has to happens in a loop to    /// // handle spurious wakeups.    /// loop {    ///     poll.poll(&mut events, None)?;    ///    ///     for event in &events {    ///         if event.token() == Token(0) && event.is_writable() {    ///             // The socket connected (probably, it could still be a spurious    ///             // wakeup)    ///             return Ok(());    ///         }    ///     }    /// }    /// # }    /// ```    ///    /// [struct]: #    pub fn poll(&mut self, events: &mut Events, timeout: Option<Duration>) -> io::Result<()> {        self.registry.selector.select(events.sys(), timeout)    }}#[cfg(all(    unix,    not(mio_unsupported_force_poll_poll),    not(any(target_os = "solaris", target_os = "vita"))))]impl AsRawFd for Poll {    fn as_raw_fd(&self) -> RawFd {        self.registry.as_raw_fd()    }}impl fmt::Debug for Poll {    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {        fmt.debug_struct("Poll").finish()    }}impl Registry {    /// Register an [`event::Source`] with the `Poll` instance.    ///    /// Once registered, the `Poll` instance will monitor the event source for    /// readiness state changes. When it notices a state change, it will return    /// a readiness event for the handle the next time [`poll`] is called.    ///    /// See [`Poll`] docs for a high level overview.    ///    /// # Arguments    ///    /// `source: &mut S: event::Source`: This is the source of events that the    /// `Poll` instance should monitor for readiness state changes.    ///    /// `token: Token`: The caller picks a token to associate with the socket.    /// When [`poll`] returns an event for the handle, this token is included.    /// This allows the caller to map the event to its source. The token    /// associated with the `event::Source` can be changed at any time by    /// calling [`reregister`].    ///    /// See documentation on [`Token`] for an example showing how to pick    /// [`Token`] values.    ///    /// `interest: Interest`: Specifies which operations `Poll` should monitor    /// for readiness. `Poll` will only return readiness events for operations    /// specified by this argument.    ///    /// If a socket is registered with readable interest and the socket becomes    /// writable, no event will be returned from [`poll`].    ///    /// The readiness interest for an `event::Source` can be changed at any time    /// by calling [`reregister`].    ///    /// # Notes    ///    /// Callers must ensure that if a source being registered with a `Poll`    /// instance was previously registered with that `Poll` instance, then a    /// call to [`deregister`] has already occurred. Consecutive calls to    /// `register` is unspecified behavior.    ///    /// Unless otherwise specified, the caller should assume that once an event    /// source is registered with a `Poll` instance, it is bound to that `Poll`    /// instance for the lifetime of the event source. This remains true even    /// if the event source is deregistered from the poll instance using    /// [`deregister`].    ///    /// [`event::Source`]: ./event/trait.Source.html    /// [`poll`]: struct.Poll.html#method.poll    /// [`reregister`]: struct.Registry.html#method.reregister    /// [`deregister`]: struct.Registry.html#method.deregister    /// [`Token`]: struct.Token.html    ///    /// # Examples    ///    #[cfg_attr(all(feature = "os-poll", feature = "net"), doc = "```")]    #[cfg_attr(not(all(feature = "os-poll", feature = "net")), doc = "```ignore")]    /// # use std::error::Error;    /// # use std::net;    /// # fn main() -> Result<(), Box<dyn Error>> {    /// use mio::{Events, Poll, Interest, Token};    /// use mio::net::TcpStream;    /// use std::net::SocketAddr;    /// use std::time::{Duration, Instant};    ///    /// let mut poll = Poll::new()?;    ///    /// let address: SocketAddr = "127.0.0.1:0".parse()?;    /// let listener = net::TcpListener::bind(address)?;    /// let mut socket = TcpStream::connect(listener.local_addr()?)?;    ///    /// // Register the socket with `poll`    /// poll.registry().register(    ///     &mut socket,    ///     Token(0),    ///     Interest::READABLE | Interest::WRITABLE)?;    ///    /// let mut events = Events::with_capacity(1024);    /// let start = Instant::now();    /// let timeout = Duration::from_millis(500);    ///    /// loop {    ///     let elapsed = start.elapsed();    ///    ///     if elapsed >= timeout {    ///         // Connection timed out    ///         return Ok(());    ///     }    ///    ///     let remaining = timeout - elapsed;    ///     poll.poll(&mut events, Some(remaining))?;    ///    ///     for event in &events {    ///         if event.token() == Token(0) {    ///             // Something (probably) happened on the socket.    ///             return Ok(());    ///         }    ///     }    /// }    /// # }    /// ```    pub fn register<S>(&self, source: &mut S, token: Token, interests: Interest) -> io::Result<()>    where        S: event::Source + ?Sized,    {        trace!(            "registering event source with poller: token={:?}, interests={:?}",            token,            interests        );        source.register(self, token, interests)    }    /// Re-register an [`event::Source`] with the `Poll` instance.    ///    /// Re-registering an event source allows changing the details of the    /// registration. Specifically, it allows updating the associated `token`    /// and `interests` specified in previous `register` and `reregister` calls.    ///    /// The `reregister` arguments fully override the previous values. In other    /// words, if a socket is registered with [`readable`] interest and the call    /// to `reregister` specifies [`writable`], then read interest is no longer    /// requested for the handle.    ///    /// The event source must have previously been registered with this instance    /// of `Poll`, otherwise the behavior is unspecified.    ///    /// See the [`register`] documentation for details about the function    /// arguments and see the [`struct`] docs for a high level overview of    /// polling.    ///    /// # Examples    ///    #[cfg_attr(all(feature = "os-poll", feature = "net"), doc = "```")]    #[cfg_attr(not(all(feature = "os-poll", feature = "net")), doc = "```ignore")]    /// # use std::error::Error;    /// # use std::net;    /// # fn main() -> Result<(), Box<dyn Error>> {    /// use mio::{Poll, Interest, Token};    /// use mio::net::TcpStream;    /// use std::net::SocketAddr;    ///    /// let poll = Poll::new()?;    ///    /// let address: SocketAddr = "127.0.0.1:0".parse()?;    /// let listener = net::TcpListener::bind(address)?;    /// let mut socket = TcpStream::connect(listener.local_addr()?)?;    ///    /// // Register the socket with `poll`, requesting readable    /// poll.registry().register(    ///     &mut socket,    ///     Token(0),    ///     Interest::READABLE)?;    ///    /// // Reregister the socket specifying write interest instead. Even though    /// // the token is the same it must be specified.    /// poll.registry().reregister(    ///     &mut socket,    ///     Token(0),    ///     Interest::WRITABLE)?;    /// #     Ok(())    /// # }    /// ```    ///    /// [`event::Source`]: ./event/trait.Source.html    /// [`struct`]: struct.Poll.html    /// [`register`]: struct.Registry.html#method.register    /// [`readable`]: ./event/struct.Event.html#is_readable    /// [`writable`]: ./event/struct.Event.html#is_writable    pub fn reregister<S>(&self, source: &mut S, token: Token, interests: Interest) -> io::Result<()>    where        S: event::Source + ?Sized,    {        trace!(            "reregistering event source with poller: token={:?}, interests={:?}",            token,            interests        );        source.reregister(self, token, interests)    }    /// Deregister an [`event::Source`] with the `Poll` instance.    ///    /// When an event source is deregistered, the `Poll` instance will no longer    /// monitor it for readiness state changes. Deregistering clears up any    /// internal resources needed to track the handle.  After an explicit call    /// to this method completes, it is guaranteed that the token previously    /// registered to this handle will not be returned by a future poll, so long    /// as a happens-before relationship is established between this call and    /// the poll.    ///    /// The event source must have previously been registered with this instance    /// of `Poll`, otherwise the behavior is unspecified.    ///    /// A handle can be passed back to `register` after it has been    /// deregistered; however, it must be passed back to the **same** `Poll`    /// instance, otherwise the behavior is unspecified.    ///    /// # Examples    ///    #[cfg_attr(all(feature = "os-poll", feature = "net"), doc = "```")]    #[cfg_attr(not(all(feature = "os-poll", feature = "net")), doc = "```ignore")]    /// # use std::error::Error;    /// # use std::net;    /// # fn main() -> Result<(), Box<dyn Error>> {    /// use mio::{Events, Poll, Interest, Token};    /// use mio::net::TcpStream;    /// use std::net::SocketAddr;    /// use std::time::Duration;    ///    /// let mut poll = Poll::new()?;    ///    /// let address: SocketAddr = "127.0.0.1:0".parse()?;    /// let listener = net::TcpListener::bind(address)?;    /// let mut socket = TcpStream::connect(listener.local_addr()?)?;    ///    /// // Register the socket with `poll`    /// poll.registry().register(    ///     &mut socket,    ///     Token(0),    ///     Interest::READABLE)?;    ///    /// poll.registry().deregister(&mut socket)?;    ///    /// let mut events = Events::with_capacity(1024);    ///    /// // Set a timeout because this poll should never receive any events.    /// poll.poll(&mut events, Some(Duration::from_secs(1)))?;    /// assert!(events.is_empty());    /// #     Ok(())    /// # }    /// ```    pub fn deregister<S>(&self, source: &mut S) -> io::Result<()>    where        S: event::Source + ?Sized,    {        trace!("deregistering event source from poller");        source.deregister(self)    }    /// Creates a new independently owned `Registry`.    ///    /// Event sources registered with this `Registry` will be registered with    /// the original `Registry` and `Poll` instance.    pub fn try_clone(&self) -> io::Result<Registry> {        self.selector.try_clone().map(|selector| Registry {            selector,            #[cfg(all(debug_assertions, not(target_os = "wasi")))]            has_waker: Arc::clone(&self.has_waker),        })    }    /// Internal check to ensure only a single `Waker` is active per [`Poll`]    /// instance.    #[cfg(all(debug_assertions, not(target_os = "wasi")))]    pub(crate) fn register_waker(&self) {        assert!(            !self.has_waker.swap(true, Ordering::AcqRel),            "Only a single `Waker` can be active per `Poll` instance"        );    }    /// Get access to the `sys::Selector`.    #[cfg(any(not(target_os = "wasi"), feature = "net"))]    pub(crate) fn selector(&self) -> &sys::Selector {        &self.selector    }}impl fmt::Debug for Registry {    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {        fmt.debug_struct("Registry").finish()    }}#[cfg(all(    unix,    not(mio_unsupported_force_poll_poll),    not(any(target_os = "solaris", target_os = "vita"))))]impl AsRawFd for Registry {    fn as_raw_fd(&self) -> RawFd {        self.selector.as_raw_fd()    }}cfg_os_poll! {    #[cfg(all(        unix,        not(mio_unsupported_force_poll_poll),        not(any(target_os = "solaris", target_os = "vita")),    ))]    #[test]    pub fn as_raw_fd() {        let poll = Poll::new().unwrap();        assert!(poll.as_raw_fd() > 0);    }}