feat: use single isolate for functions and postgrest

[dshukertjr]

What kind of change does this PR introduce?

Instantiates a single instance of YAJsonIsolate and reuses it for Postgrest and functions-dart.

[Vinzent03]

Don't we want the user to be able to provide their own isolate instance? Additionally, I think we should call initialize() on it and like in postgrest dispose it correctly.

[dshukertjr]

@Vinzent03 Hmm, still trying to figure out why test started failing massively once I added initialize() and dispose().

About making it possible to pass custom isolate, would there be any use case where one might want to pass in their custom isolate? I'm a fan of keeping the public API simple, so maybe we can wait until someone requests the feature.

[Vinzent03]

When reverting d804f05 all tests pass for me locally. The isolate.dispose() waits until the init is finished, but doesn't call the init if it has never started.

The use case for keeping the same isolate would be server side for me. Because of the current api you have to construct a new supabase-dart instance every time you want to act as a different user. Being able to keep the same isolate for these short living instances could improve performance.

[dshukertjr]

@Vinzent03 Yeah, I have misread something, and it seems like calling initialize() not the issue. With initialize() being called, the tests do pass for me locally as well, but in Github actions, we get this.

The use case for keeping the same isolate would be server side for me.

Ah, I always forget server side Dart 😂 Yup, sounds good. Let's add an option to pass in an isolate to Supabase client!

[dshukertjr]

Leaving a note here:

Using web_socket_channel v2.3.0 causes the tests to fail like this. Fixing the version of web_socket_channel to v2.2.0 solves the issue for now.

[bdlukaa]

lgtm overall

[Vinzent03]

LGTM