refactor: Destructure read_event() path

Pass in all the in/out parameters individually instead of taking
everything out of peer.

The important thing to notice here is that the pending_outbound_buffer
parameter MUST be an OutboundQueue and CANNOT be an 'impl PayloadQueuer'.
This demonstrates that the read_event() function has the ability to
flush() since it can use the SocketDescriptorFlusher interface.

This should be illegal due to the invariant that read_event() never
calls back into the SocketDescriptor.

This is one of the motivations of using trait bounds in argument
position as a defensive programing technique to prohibit functions from
taking actions that shouldn't be allowed even if they have access to the
object.

Future patches will fix this bug and ensure the type system enforces
this bug from happening again.

This is a short-lived destructure that will be recombined once the
dependencies are cleaned up.

Author: julianknutsen