* Add NIOAsyncChannel based connect methods to ClientBootstrap
# Motivation
In my previous PR, I added new `bind` methods to `ServerBootstrap` that vend `NIOAsyncChannel` or support an async protocol negotiation. This PR focuses on adding new `connect` methods to `ClientBootstrap` which offer the same functionality.
# Modification
This PR adds new `connect` methods that either vend a `NIOAsyncChannel` or an asynchronous protocol negotiation result. To make this work I had to change the `HappyEyeballs` resolver so that it can return a generic value on resolving. Lastly, I adapted the bootstrap tests to use the new `ClientBootstrap` capabilities which now demonstrate a client/server protocol negotiation dance.
# Result
We can now bootstrap TCP clients with `NIOAsyncChannel`s
* Reduce code duplication
* Create a new set of APIs to tunnel an arbitrary Sendable payload through the inits
* Pass EL to closure
* Fix documentation
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