Notes on memory use ( from heap dumps ):
- buffers are not yet recycled ( the BBuffers used in channels )

- each active connection consumes at least 26k - 2 buffers + head buffer
( 8k each )
TODO: could 'peak' in the In buffer and move headRecv to HttpChannel


- HttpChannel keeps about 64K ( for the hello world ).
-- res is 25k
-- req is 32k, BufferedIOReader 16k,

TODO:
- leak in NioThread.active - closed sockets not removed
- need to rate-limit and queue requests - OOM
- timeouts
- seems few responses missing on large async requests (URL works)