Wrapper around AFUNIXSocket that is bound to a fixed address and will
ignore the argument passed to 'connect'. This is necessary since an HTTP
client using this socket will pass its own socket address.

SocketFactory that produces `FixedPathTcpSocket` objects bound to a fixed path.

Wrapper around AFUNIXSocket that is bound to a fixed address and will
ignore the argument passed to 'connect'. This is necessary since an HTTP
client using this socket will pass its own socket address.

SocketFactory that produces `FixedPathUnixSocket` objects bound to a
given path.

Wrapper around an existing socket that will make sure that the originating
OkHttp Response is closed when the socket is closed. Without this, we
run into connection leaks.

Wrapper around a `SocketFactory` that will cache the created socket.

Implementation of OkHttp's RequestBody that streams some data.