Motivation:
Previously we were not running the (child/server)channelInitializers on the
event loop associated to the `Channel` we're initialising. Almost all
operations in there are pipeline modifications which are thread safe so
it presumably wasn't a massive correctness issue. However it's very
expensive to hop threads that often and it is also very unexpected. This
addresses this issue.
Modifications:
made all (child/server)channelInitializers run on the event loop that is
associated to their `Channel`
Result:
- more correctness
- less unexpected behaviour