Mitigate large futures

Signed-off-by: Jason Volk <jason@zemos.net>

src/api/client/state.rs

@@ -59,6 +59,7 @@ pub(crate) async fn send_state_event_for_empty_key_route(
 	body: Ruma<send_state_event::v3::Request>,
 ) -> Result<RumaResponse<send_state_event::v3::Response>> {
 	send_state_event_for_key_route(State(services), body)
+		.boxed()
 		.await
 		.map(RumaResponse)
 }