PEP 818: Adding the Core of the Pyodide Foreign Function Interface to Python (2)

This is the second discuss thread for PEP 818. The previous thread is here. I got the following feedback: Various name changes were requested, which I implemented. The PEP was too long, so I reduced the length by about half by removing implementation details from the spec section. I also added support for proxying and conversion of buffers, and for asyncio including an event loop, conversion between Python and JavaScript awaitables, and deferred destruction for arguments to an asynchronous Ja...