research the idea of using zig's async/yield to manage nif scheduling about zigler

[ityonemo]

moving to milestone 0.1.4.
using zig's async/yield seems like it's not really an option. Instead, we should use zig's multithreading system, and spawn to a remote thread, returning a message callback to check on the function result. This result will be stashed inside of a resource, to permit erlang to properly manage it using the GC.

[ityonemo]

basic idea of performing async long functions is completed here: a72055b

the entire outline of all the moving parts necessary is described in this code, and is tested to be working. What follows next is making this code generic.

https://github.com/ityonemo/zigler/blob/async/test/async_test.exs

[ityonemo]

moving to milestone 0.2.0 because this hugely benefits from parser refactoring.

[ityonemo]

moving to 1.0.0 to wait for zig 0.6.0 async

[ityonemo]

completed here #201