public void StartSendInitialMetadata(SendCompletionHandler callback, MetadataArraySafeHandle metadataArray) { using (completionQueue.NewScope()) { var ctx = BatchContextSafeHandle.Create(); completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success)); pinvoke.grpcsharp_call_send_initial_metadata(this, ctx, metadataArray).CheckOk(); } }