Trace calls to Session.send with opencensus-ext-requests

[d-webs]

Is your feature request related to a problem?

In certain cases when using a requests.Session object, it may be helpful to to use prepared requests. When using requests.Session.send, however, traces are unexpectedly missing. The reason for this is because the opencensus-ext-requests only patches the Session.request function (which get, post, patch, etc. ultimately call), but not send.

References:

• Session.send source code
• opencensus-ext-requests Session.request wrapper

Describe the solution you'd like. Wrap calls to Session.send in addition to Session.request

Describe alternatives you've considered. N/A

Additional context. N/A