The purpose of this patch is to make the arguments cowboy passes to
error_logger more consistent. With this patch there's only 3 variations
on the error_logger argument list; a 5 element list, an 8 element list
and a 10 element list. In all cases, the first 3 arguments are the
Module, Function and Arity of the function being called and the
second-to-last argument is always the Request. Additionally, for lists
longer than 5 elements, the last argument is always the stack-trace.
The added consistency of the argument ordering makes it much easier to
write code in lager's error_logger handler to catch these messages and
write a pretty one-liner (while writing the full message to the
crash.log).
We can now reply empty close, ping and pong frames, or close
frames with a payload.
This means that we can send a frame and then close the connection
in a single operation.
If a close packet is sent, the connection is closed immediately,
even if there was frames that remained to be sent. Cowboy will
silently drop any extra frames in the list given as a reply.
In some situations, the underlying socket might become "half-open" in
which case the websocket will stay in a waiting state indefinitely. The
detection of this state requires checking for errors when calling send.
Header names are now binaries. Since header names are case insensitive
they are all converted to lowercase. For example: <<"content-length">>.
The max_line_length option was removed. Three new options have been
added instead:
* max_request_line_length (defaults to 4096)
* max_header_name_length (defaults to 64)
* max_header_value_length (defaults to 4096)
