If the capacity is zero or absent, the channel is unbuffered and communication
succeeds only when both a sender and receiver are ready. Otherwise, the channel
is buffered and communication succeeds without blocking if the buffer
is not full (sends) or not empty (receives).
A <code>nil</code> channel is never ready for communication.
</p>

<p>
A channel may be closed with the built-in function

pkg io, func NopCloser(Reader) ReadCloser
pkg io, func ReadAll(Reader) ([]uint8, error)
pkg io, type ReadSeekCloser interface { Close, Read, Seek }
pkg io, type ReadSeekCloser interface, Close() error
pkg io, type ReadSeekCloser interface, Read([]uint8) (int, error)
pkg io, type ReadSeekCloser interface, Seek(int64, int) (int64, error)
pkg io, var Discard Writer
pkg io/fs, const ModeAppend = 1073741824

pkg syscall (netbsd-arm64-cgo), func RawSyscall(uintptr, uintptr, uintptr, uintptr) (uintptr, uintptr, Errno)
pkg syscall (netbsd-arm64-cgo), func ReadDirent(int, []uint8) (int, error)
pkg syscall (netbsd-arm64-cgo), func Read(int, []uint8) (int, error)
pkg syscall (netbsd-arm64-cgo), func Recvfrom(int, []uint8, int) (int, Sockaddr, error)
pkg syscall (netbsd-arm64-cgo), func Recvmsg(int, []uint8, []uint8, int) (int, int, int, Sockaddr, error)