Improve aquatic_ws glommio implementation, fixing memory leak (#37)

* ws: upgrade tungstenite and async-tungstenite to 0.16

* ws: use latest glommio

* ws: glommio: add config key connection_cleaning_interval

* ws: glommio: limit socket worker local channel size

Quick fix for memory leak

* ws: glommio: use prioritized task queue for sending responses

This is a start on trying to fix the large amount of responses
being dropped due to local response channel being full

* scripts/watch-threads.sh: don't highlight changes

* ws: glommio: await when sending responses from shared to local

* ws: glommio: limit ws message queue; add lots of ::log::warn for debug

* ws: glommio: add timeout to send_out_message, maybe pinpointing issue

* ws: glommio: clean up, tweak channel sizes; update TODO

* ws: glommio: set send timeout to 10s, add backpressure, accept drops

* ws: glommio: yield if needed in ConnectionReader backoff loop

* ws load test: add config key connection_creation_interval_ms

* ws load test: don't print "run connection" when opening connection

* ws load test: rename config num_connection to num_connections_per_worker

* ws load test config: improve order of code in file

* ws: glommio: info-level log for socket send timeout

* ws glommio: clean idle connections, improve cleaning code

* ws: glommio: make ConnectionWriter::send_error_response fallible; fmt

* ws: glommio: store JoinHandle in conn reference, cancel task on clean

* add scripts/heaptrack.sh

* Update TODO

scripts/heaptrack.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+heaptrack --pid $(pgrep "^aquatic_[a-z]{1,4}$")