This reduces the number of times we need to ask for more packets,
and as a result we get a fairly large boost in performance,
especially with HTTP/1.1.
Unfortunately this makes Cowboy require at least Erlang/OTP 21.3+
because the ssl application did not have active,N. For simplicity
the version required will be Erlang/OTP 22+.
In addition this change improves hibernate handling in
cowboy_websocket. Hibernate will now work for HTTP/2 transport
as well, and stray or unrelated messages will no longer cancel
hibernate (the process will handle the message and go back into
hibernation).
Thanks go to Stressgrid for benchmarking an early version of this
commit: https://stressgrid.com/blog/cowboy_performance_part_2/
We now stop reading from the socket unless asked to,
when we reach the request body. The option
initial_stream_flow_size controls how much data
we read without being asked, as an optimization.
We may also have received additional data along
with the request headers.
This commit also reworks the timeout handling for HTTP/1.1
because the stray timeout message was easily reproducible
after implementing the flow control. The issue should be
gone for good this time.
It allows disabling the chunked transfer-encoding. It
can also be disabled on a per-request basis, although
it will be ignored for responses that are not streamed.
They are now cowboy:start_clear/3 and cowboy:start_tls/3.
The NumAcceptors argument can be specified via the
num_acceptor transport option. Ranch has been updated
to 1.4.0 to that effect.
