// Network file descriptor.typenetFDstruct {
pfdpoll.FD// immutable until ClosefamilyintsotypeintisConnectedbool// handshake completed or use of association with peernetstringladdrAddrraddrAddr}
// poll.FD// FD is a file descriptor. The net and os packages embed this type in// a larger type representing a network connection or OS file.typeFDstruct {
// Lock sysfd and serialize access to Read and Write methods.fdmufdMutex// System file descriptor. Immutable until Close.Sysfdsyscall.Handle// Read operation.ropoperation// Write operation.wopoperation// I/O poller.pdpollDesc// Used to implement pread/pwrite.lsync.Mutex// For console I/O.lastbits []byte// first few bytes of the last incomplete rune in last writereaduint16 []uint16// buffer to hold uint16s obtained with ReadConsolereadbyte []byte// buffer to hold decoding of readuint16 from utf16 to utf8readbyteOffsetint// readbyte[readOffset:] is yet to be consumed with file.Read// Semaphore signaled when file is closed.csemauint32skipSyncNotifbool// Whether this is a streaming descriptor, as opposed to a// packet-based descriptor like a UDP socket.IsStreambool// Whether a zero byte read indicates EOF. This is false for a// message based socket connection.ZeroReadIsEOFbool// Whether this is a file rather than a network socket.isFilebool// The kind of this file.kindfileKind}