Fix RPC invocation race condition (#565)

* Fix race condition in rpc invocation

* nanpa

* fix

* nanpa

* cgo

* sm

Author: bcherry

.nanpa/rpc-race.kdl

@@ -0,0 +1 @@
+patch package="livekit-ffi" type="fixed" "Fix RPC invocation race bug"

livekit-ffi/src/server/participant.rs

@@ -140,6 +140,8 @@ async fn forward_rpc_method_invocation(
     let (tx, rx) = oneshot::channel();
     let invocation_id = server.next_id();
 
+    room.store_rpc_method_invocation_waiter(invocation_id, tx);
+
     let _ = server.send_event(proto::ffi_event::Message::RpcMethodInvocation(
         proto::RpcMethodInvocationEvent {
             local_participant_handle: local_participant_handle as u64,
@@ -152,8 +154,6 @@ async fn forward_rpc_method_invocation(
         },
     ));
 
-    room.store_rpc_method_invocation_waiter(invocation_id, tx);
-
     rx.await.unwrap_or_else(|_| {
         Err(RpcError {
             code: RpcErrorCode::ApplicationError as u32,