Add async-std support and replaced reqwest with surf (#58)

[JEnoch]

Description

This PR replaces reqwest usage with surf usage that supports both tokio and async-std. It also modifies the tests to run with both.
Fixes #58.

Checklist

• Formatted code using cargo fmt --all
• Linted code using clippy cargo clippy --all-targets --all-features -- -D warnings
• Updated README.md using cargo readme -r influxdb -t ../README.tpl > README.md
• Reviewed the diff. Did you leave any print statements or unnecessary comments?
• Any unfinished work that warrants a separate issue captured in an issue with a TODO code comment

[Empty2k12]

Thanks for this PR!

Could we add two flags (async-std and tokio) and have tokio being the default one. If tokio is enabled, the hyper backend of surf is used, and if async-std is enabled, the curl backend is used?

Also, I'd like to merge #73 first, so the changed calls can be ported over to surf as well.

[JEnoch]

I'm not sure to understand the purpose of adding async-std and tokio features. Your influxdb-rust library is actually agnostic to async-std or tokio, as surf is as well.
I made some tests with surf and you mixing hyper-client or curl-client with either async-std or tokio for the binary's main() works in all combinations.

But you're right about giving the user the possibility to choose the http backend.
If you agree, I add in this PR the same features than surf in influxdb-rust (See https://github.com/http-rs/surf/blob/main/Cargo.toml#L19). And set hyper-client as default if you prefer.

[JEnoch]

Hi @Empty2k12,

I updated this PR with latest status, merging with #73.
I also added the features to choose the http library used by surf (default to hyper-client), following my proposal above.

Note that switching to surf I get a 50% perf improvement on the bench pushed in #73 and no request errors (I had a lot when using reqwest) !

[JEnoch]

Hi @Empty2k12 ,

Any concern or issue reviewing this PR ?

[Empty2k12]

Sorry, I'm quite busy with university right now. Tested your PR and will merge it now.
Thanks for this contribution! 🚀

[JEnoch]

Thanks for the merge! (and sorry for the "harassment" 😉 )
Do you plan a release and publication to crates.io any time soon ?

[Empty2k12]

@JEnoch Yes, I plan releasing this as 0.3.0.

[Empty2k12]

@JEnoch The version is now available under 0.3.0 at crates.io: https://crates.io/crates/influxdb

Thanks again for your contribution!

[JEnoch]

@Empty2k12 That's great, thanks a lot! I just made eclipse-zenoh to use it (eclipse-zenoh/zenoh@a206fa83).