/// Sends a given `event` to the room.
  pub(crate) async fn send(
      &self,
      event_type: TimelineEventType,
      state_key: Option<String>,
      content: Box<RawJsonValue>,
      future: Option<future::FutureParameters>,
  ) -> Result<SendEventResponse> {
      let type_str = event_type.to_string();
      Ok(match (state_key, future) {
          (None, None) => SendEventResponse::from_event_id(
              self.room.send_raw(&type_str, content).await?.event_id,
          ),
          (Some(key), None) => SendEventResponse::from_event_id(
              self.room.send_state_event_raw(&type_str, &key, content).await?.event_id,
          ),
          (None, Some(future)) => {
              let r = future::send_future_message_event::unstable::Request::new_raw(
                  self.room.room_id().to_owned(),
                  TransactionId::new().to_owned(),
                  MessageLikeEventType::from(type_str),
                  future,
                  Raw::<AnyMessageLikeEventContent>::from_json(content),
              );
              self.room.client.send(r, None).await.map(|r| r.into())?
          }
          (Some(key), Some(future)) => {
              let r = future::send_future_state_event::unstable::Request::new_raw(
                  self.room.room_id().to_owned(),
                  key,
                  StateEventType::from(type_str),
                  future,
                  Raw::<AnyStateEventContent>::from_json(content),
              );
              self.room.client.send(r, None).await.map(|r| r.into())?
          }
      })