membership.rs

                "Error while handling incoming PDU.",
            )
        })?
        .ok_or(Error::BadRequest(
            ErrorKind::InvalidParam,
            "Could not accept incoming PDU as timeline event.",
        ))?;

        for server in db
            .rooms
            .room_servers(room_id)
            .filter_map(|r| r.ok())
            .filter(|server| &**server != db.globals.server_name())
        {
            db.sending.send_pdu(&server, &pdu_id)?;
        }

        return Ok(());
    }

    let mutex_state = Arc::clone(
        db.globals
            .roomid_mutex_state
            .write()
            .unwrap()
            .entry(room_id.clone())
            .or_default(),
    );
    let state_lock = mutex_state.lock().await;

    db.rooms.build_and_append_pdu(
        PduBuilder {
            event_type: EventType::RoomMember,
            content: serde_json::to_value(member::MemberEventContent {
                membership: member::MembershipState::Invite,
                displayname: db.users.displayname(&user_id)?,
                avatar_url: db.users.avatar_url(&user_id)?,
                is_direct: Some(is_direct),
                third_party_invite: None,
                blurhash: db.users.blurhash(&user_id)?,
            })
            .expect("event is valid, we just created it"),
            unsigned: None,
            state_key: Some(user_id.to_string()),
            redacts: None,
        },
        &sender_user,
        room_id,
        &db,
        &state_lock,
    )?;

    drop(state_lock);

    Ok(())
}