v0.13.0

• IO::Stream::Duplex(io) is equivalent to IO::Stream(io).

v0.12.0

• Introduce IO::Stream::Duplex as a low-level duplex transport for composing separate input and output endpoints.
• Add IO::Stream::Duplex(input, output) as a convenient constructor that returns a buffered stream wrapping a duplex transport.
• Add a timeout compatibility shim for StringIO so duplex streams composed from in-memory endpoints can participate in the timeout interface consistently.
• Remove old OpenSSL method shims.