This commit refactors both wsutil, the normal Gateway and the Voice
Gateway to have better closing behavior, which should assume less and
cover edge cases completely.
This commit fixes race conditions in both package voice, package
voicegateway and package gateway.
Originally, several race conditions exist when both the user's and the
pacemaker's goroutines both want to do several things to the websocket
connection. For example, the user's goroutine could be writing, and the
pacemaker's goroutine could trigger a reconnection. This is racey.
This issue is partially fixed by removing the pacer loop from package
heart and combining the ticker into the event (pacemaker) loop itself.
Technically, a race condition could still be triggered with care, but
the API itself never guaranteed any of those. As events are handled
using an internal loop into a channel, a race condition will not be
triggered just by handling events and writing to the websocket.
diamondburned
