Improve channels implementation

[flcl42]

Is your feature request related to a problem? Please describe.
The current implementation is not optimal and does not implement backpush properly.
It should be also reviewed for memory allocation efficiency and be covered by tests.

Describe the solution you'd like
Implement pushback-enabled bidirectional channel that exposes an API for optimal buffer allocation and decreases coping while passing data between protocols.

Describe alternatives you've considered
Standard Channels require the current API deep rethinking to integrate them, let's consider this option.
Another approach is to define API that allows direct communication between protocol layers.
https://learn.microsoft.com/en-us/dotnet/standard/io/pipelines?

Additional context
Channels are used to pass data received from the network through the protocol stack.
They are also used to control lifetime and signal about communication ending(which can be forced or regular).