bumpup and clamp connection timeout, fix the comment (#893)

This PR fixes the comment for PerformRpcParams, bump up the RPC
connection time out to 7 seconds, and also clamp the connection response
timeout if needed.

See similar PR on JS SDK:
livekit/client-sdk-js#1694

Co-authored-by: Hiroshi Horie <[email protected]>

Author: xianshijing-lk

lib/src/participant/local.dart

@@ -1043,16 +1043,21 @@ extension RPCMethods on LocalParticipant {
     final requestId = Uuid().v4();
     final completer = Completer<String>();
 
-    final maxRoundTripLatency = Duration(seconds: 2);
+    final maxRoundTripLatency = Duration(seconds: 7);
+    final minEffectiveTimeout = const Duration(milliseconds: 1000);
 
     try {
+      final effectiveTimeout = Duration(
+        milliseconds: (params.responseTimeoutMs.inMilliseconds - maxRoundTripLatency.inMilliseconds)
+            .clamp(minEffectiveTimeout.inMilliseconds, double.infinity)
+            .toInt(),
+      );
       await publishRpcRequest(
         destinationIdentity: params.destinationIdentity,
         requestId: requestId,
         method: params.method,
         payload: params.payload,
-        responseTimeout:
-            Duration(milliseconds: params.responseTimeoutMs.inMilliseconds - maxRoundTripLatency.inMilliseconds),
+        responseTimeout: effectiveTimeout,
         version: kRpcVesion,
       );
 

lib/src/types/rpc.dart

@@ -10,14 +10,17 @@ class PerformRpcParams {
   /// The payload of the request.
   String payload;
 
-  /// The maximum time the caller will wait for a response.
+  /// Timeout for receiving a response after the initial connection (in milliseconds).
+  /// If a value less than 8000 ms is provided, it will be automatically clamped to 8000 ms
+  /// to ensure sufficient time for round-trip latency buffering.
+  /// Default: 15000 ms.
   Duration responseTimeoutMs;
 
   PerformRpcParams({
     required this.destinationIdentity,
     required this.method,
     required this.payload,
-    this.responseTimeoutMs = const Duration(milliseconds: 10000),
+    this.responseTimeoutMs = const Duration(milliseconds: 15000),
   });
 }