Use gateway url provided in `Ready` event for resuming

[lukellmann]

relevant doc commits:

• https://github.com/discord/discord-api-docs/commit/30b37e576d3457f5401c50dea96e8bc5bfdd675b
• https://github.com/discord/discord-api-docs/commit/58d6ec4ba99018c2fc104428c0309081b14d9fb3

[HopeBaron]

I reviewed the PR a second time and it looks fine; but it's a draft so I'll be waiting til it's complete

[lukellmann]

I made it a draft because of this concern:

I think it might be necessary to reset the context on some other Close events, e.g. UserClose (resuming after the user stopped the gateway seems wrong). I'm new to gateway code, so I might be wrong here, what do you think?

But if you say this isn't needed, then this PR is ready.

[HopeBaron]

The resume will not need to modify anything because the reset or not is handled by the loop conditions all what changed in this PR is where should we connect on resumes not how we should connect so I guess we are good to go if you have tested it and left the bot running for a bit with, say "turn on turn off network to test how would that go

[lukellmann]

Problem is that I can't really test rn because they only send the default url until September 12 (which means we connect to the same as normal until then).

[HopeBaron]

In that case guess there is no need to rush and merge as this may be subject to change

[lukellmann]

Converted this back to a draft for now

[lukellmann]

I checked rn, I'm still not receiving a session-specific URL. Will try again later today/tomorrow.

[lukellmann]

I checked rn, I'm still not receiving a session-specific URL. Will try again later today/tomorrow.

Still no luck... 😞

[lukellmann]

Still nothing, what should we do?

[lukellmann]

I was finally able to receive a different url and test it - seems to work as intended