Document concurrency

I'm curious what model is used to bridge Python and golang concurrency models.
I wish it was documented :)

Python has threads (1:1 mapped to lightweight system processes) and asyncio, explicit and quite so different.

Go has special handling for cpu-bound and io-bound goroutines, transparent to the user.

How would someone use `gopy` to interface go's amazing `net/http` module or some go package that wraps it? As in, how should Python code look like to benefit from go's concurrency?

The issue names gopy and Go's net/http, but no files or tests. Start by reviewing gopy's existing documentation and the generated CPython extension behavior, then determine how a Python caller would use a Go package with concurrency. Done means the documentation explains the Python/Go concurrency bridge and shows how to use a package such as net/http.

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