Suppress JsonRPC Empty Response Exception and refactor code

Author: taooceros

Flow.Launcher.Core/Plugin/JsonRPCPlugin.cs

@@ -254,6 +254,14 @@ protected async Task<Stream> ExecuteAsync(ProcessStartInfo startInfo, Cancellati
                 return Stream.Null;
             }
 
+
+
+            var sourceBuffer = BufferManager.GetStream();
+            var errorBuffer = BufferManager.GetStream();
+
+            var sourceCopyTask = process.StandardOutput.BaseStream.CopyToAsync(sourceBuffer, token);
+            var errorCopyTask = process.StandardError.BaseStream.CopyToAsync(errorBuffer, token);
+            
             token.Register(() =>
             {
                 try
@@ -266,14 +274,6 @@ protected async Task<Stream> ExecuteAsync(ProcessStartInfo startInfo, Cancellati
                 }
             });
 
-
-            var sourceBuffer = BufferManager.GetStream();
-            var errorBuffer = BufferManager.GetStream();
-
-            var sourceCopyTask = process.StandardOutput.BaseStream.CopyToAsync(sourceBuffer, token);
-            var errorCopyTask = process.StandardError.BaseStream.CopyToAsync(errorBuffer, token);
-
-
             try
             {
                 // token expire won't instantly trigger the exception,