title: Async http requests with ETag caching
body: <p>I'm currently using <code>Requests</code> with <code>CacheControl</code> in my project, and am trying to migrate to an async approach.</p>
  <p>There seem to be lots of great options out there for making async http requests. <code>httpx</code>, trio's <code>asks</code>.. etc.</p>
  <p>Unfortunately I've struggled to find any existing solutions that have ETag based request caching functionality.</p>
  <p>Am I missing an option that's out there, or is this just a gap that hasn't been filled yet?</p>