This crate defines StreamReader, StreamWriter, and StreamDuplexer
types which provide safe, owning, unbuffered, and unlocked access to a raw I/O
stream, such as standard input, standard output, files, sockets, or pipes. It
also supports a "piped thread" concept, where an arbitrary
Box<dyn Read + Send> or Box<dyn Write + Send> can be provided, and the I/O
is performed on a thread and connecting to the StreamReader or StreamWriter
with a pipe, and a "socketed thread" concept, where a provided function is
called on a thread and connected to the main thread via a bidirectional socket.
On Posix-ish platforms, including limited support for WASI, these types just
contain a single file descriptor (and implement AsRawFd), plus any
resources needed to safely hold the file descriptor live. On Windows, they
contain an enum holding either RawHandle or RawSocket.
Since these types are unbuffered, it's advisable for most use cases to wrap
them in buffering types such as std::io::BufReader, std::io::BufWriter,
std::io::LineWriter, io_streams::BufDuplexer, or
io_streams::BufReaderLineWriter.
Rust's std::io::Stdin and std::io::Stdout are always buffered, while
its std::fs::File and std::net::TcpStream are unbuffered. A key purpose
of the io_streams crate is to abstract over the underlying inputs and outputs
without adding buffering, so that buffering can be applied without redundancy.
This crate locks stdio::io::Stdin and std::io::Stdout while it has their
corresponding streams open, to prevent accidental mixing of buffered and
unbuffered output on the same stream. Attempts to use the buffered streams when
they are locked will block indefinitely.