Feature/mtu remove raise state (#156)

* copied perf test from sendmmsg branch

* trailing whitespace

* fix some warnings, add warnings to build

* cleanup warnings

* remove mtu-raise-timer and related state

Don't tear down stream queues until after handles have closed (#155)

Clear connected status on stream close (#153)

Close MTU timer on stream close (#151)

* Close MTU timer on stream close

* `stream->err` -> `stream->error`

Call `on_firewall` when receiving data on a different socket (#148)

Return error if trying to relay to closed stream (#149)

Feature/change remote add socket (#147)

* copied perf test from sendmmsg branch

* trailing whitespace

* change socket on change_remote call, crash fix.

* always set pkt->fifo_gc and pkt->send_queue when queueing a packet

* win fix

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Co-authored-by: Kasper Isager Dalsgarð <kasperisager@hey.com>

Test destroying old streams on changing remote (#145)

Fix `udx_stream_write()` status code when drained (#144)

Feature/change remote address (#143)

* copied perf test from sendmmsg branch

* trailing whitespace

* change remote address api

* malloc.h->stdlib.h

* Apply suggestions from code review

Co-authored-by: Kasper Isager Dalsgarð <kasperisager@hey.com>

* updated change-remote test to use built-in relay

* fixup remote address before invoking on_remote_change callback

* testing if the mac testrunner fails due to 127.0.0.[234] addresses

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Co-authored-by: Kasper Isager Dalsgarð <kasperisager@hey.com>