PYTHON-3691 [Build Failure] test_client.TestClient.test_exhaust_network_error (#1216)

pymongo/pyopenssl_context.py

@@ -107,6 +107,11 @@ class _sslConn(_SSL.Connection):
             try:
                 return call(*args, **kwargs)
             except BLOCKING_IO_ERRORS as exc:
+                # Check for closed socket.
+                if self.fileno() == -1:
+                    if timeout and _time.monotonic() - start > timeout:
+                        raise _socket.timeout("timed out")
+                    raise SSLError("Underlying socket has been closed")
                 if isinstance(exc, _SSL.WantReadError):
                     want_read = True
                     want_write = False