feat: Add SpawnService and SpawnedReqwestConnector for running requests on a different runtime

[ion-elgreco]

Which issue does this PR close?

• closes [object_store] Run requests on a different tokio runtime #13

Adds support for spawning reqwuests tasks to another Runtime. Credits to @tustvold, I simply added an additional connector in there to make it easier for others to integrate this in their code base.

• Port of [ObjectStore] Add SpawnService for running requests on different tokio runtime/Handle arrow-rs#7253

Example:

  let prefix = Path::parse(path)?;
  let mut builder = MicrosoftAzureBuilder::new().with_url(url.to_string());
  for (key, value) in config.iter() {
      builder = builder.with_config(*key, value.clone());
  }
  let inner = builder
      .with_retry(self.parse_retry_config(options)?)
      .with_http_connector(SpawnedReqwestConnector::new(io_handle))
      .build()?;

Rationale for this change

Allows a separation of cpu bound tasks and io bound tasks

What changes are included in this PR?

• Adds a SpawnService
• Adds a SpawnedReqwestConnector

Are there any user-facing changes?

Only an additional http_connector.

cc @alamb 😃

[alamb]

Thank you @ion-elgreco (and @tustvold ) -- this is great.

I think it would help a lot of we could add some more documentation / examples

Basically, imagine someone coming to https://docs.rs/object_store/latest/object_store/

1. How would they find out about this feature / decide when to use it
2. How would they be able to use it?

Perhaps we could

1. Add a brief section after TLS Certificiates with a pointer to the src/client/http module
2. Add some documentation examples in http with pointers to SpawnService

I can try and help with this documentation later this week

Example:

Is there any chance you can add this example somewhere?

[alamb]

FYI @kylebarron

[ion-elgreco]

@alamb sure! I'll add more docs tomorrow

[ion-elgreco]

@alamb I've added some docs

[alamb]

Note due to #335 the CI was not running. I plan to merge up from main shortly

[alamb]

Thank you @ion-elgreco 🙏

As I mentioned I spent a while longer today updating the docs and adding some more tests. I think this PR is now ready to rock. Thank you so much

This completes a feature we have been talking about / discussing for over a year. 💯 🦾 !

FYI @crepererum and @tustvold

[alamb]

I also wrote this end to end integration test to ensure that everything worked correctly when hooked up to an ObjectStore implementation (and it does!)

[alamb]

if you comment out this line the test fails

[alamb]

I am out starting tomorrow for a week, so if another committer doesn't merge this before I will do so when I get back

Thanks again @ion-elgreco

[tustvold]

This appears to have accumulated some merge conflicts

[alamb]

This appears to have accumulated some merge conflicts

I'll try and fix it

[ion-elgreco]

@alamb resolved the merge conflict with the new Zed merge conflict functionality :P

[alamb]

I am looking at the WASM issue

[alamb]

I think we are ready , let's merge this in!

[alamb]

Thanks again @ion-elgreco for helping push this over the line