feat: implementation of collector http client with pure hyper

[tomkarw]

Closes #843.

[linux-foundation-easycla]

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• ✅ login: tomkarw / name: Tomek Karwowski (39b05fd, cd193b7, dc71deb)

[tomkarw]

Hey @TommyCpp, I have no idea why the cargo doc keeps failing. I fixed a couple of the errors (even in unrelated parts of the code base), but this latest one in opentelemetry-proto is too much for me. I can't even reproduce it locally (the local docs look fine, and it's a crate that is not pushed publicly).

Could you lend me a hand, or maybe I can just [allow(clippy::...)] it?

[TommyCpp]

Hey @TommyCpp, I have no idea why the cargo doc keeps failing. I fixed a couple of the errors (even in unrelated parts of the code base), but this latest one in opentelemetry-proto is too much for me. I can't even reproduce it locally (the local docs look fine, and it's a crate that is not pushed publicly).

Could you lend me a hand, or maybe I can just [allow(clippy::...)] it?

Thanks! coverage uses nightly build so it may have additional lint issue. I won't worry it too much. I will take a look and open a PR to fix it if needed.

[tomkarw]

Hey @TommyCpp,

I've added hyper-with-tls support and refactored feature-conditional imports.

I deem this PR ready for review now.

[TommyCpp]

LGTM. Thanks!