Add support for multiple stream handlers

The stream handlers can be specified using the protocol
option 'stream_handlers'. It defaults to [cowboy_stream_h].

The cowboy_stream_h module currently does not forward the
calls to further stream handlers. It feels like an edge
case; usually we'd want to put our own handlers between
the protocol code and the request process. I am therefore
going to focus on other things for now.

The various types and specifications for stream handlers
have been updated and the cowboy_stream module can now
be safely used as a behavior. The interface might change
a little more, though.

This commit does not include tests or documentation.
They will follow separately.

0 files changed, 0 insertions, 0 deletions