For GRPCOperation's, ensure finish _handler can only be called once, and release it when called, so weak ptrs needn't be used with it, and the call won't be released until the finish handler is called.
When the connectivityMonitor determines the connection has been lost, pull the host disconnect call. Creates an unreliable connection when connectivity is restored. Calling finishWithError: is sufficient.

Replace liquid templates with relative links.

Implemented compression level algorithms properly (as a function of the accepted algorithms by the call's peer.

Apparently Python can call arbitrarily deallocation code whenever its
allocator is invoked, which can cause output from gRPC core to stderr,
which can happen on the thread that is emptying the stderr pipe, thus
causing the stderr pipe to deadlock on itself.

Both have to do with the test runner's handling of the tests. With one
it's the read thread somehow outliving the other threads (e.g. with
ctrl-C). The other is due to a filled OS-level pipe's buffer causing a
block while code is still holding the GIL in some gRPC core function. We
can't empty the buffer from Python because the GIL is held, and the OS
can't unblock because it's waiting for the buffer to get cleared:
deadlock.