Supporting void function return type

examples/example.jrpc

@@ -28,6 +28,7 @@ type AddValueResponse {
 service TestService {
    AddValuesSingleParam(request: AddValueRequest): AddValueResponse;
    AddValuesMultipleParams(value1: number, value2: number): number;
+   ReturningVoid(param1: number): void;
 
    notification OnEvent(param1: string);
 }

examples/test.ts

@@ -32,6 +32,10 @@ class TestService extends Server.TestService<undefined> {
       return value1 + value2;
    }
 
+   async ReturningVoid(param1) {
+      console.log("Calling Returning Void");
+   }
+
    OnEvent(param1: string, ctx: undefined): void {
       console.log("Received notification", param1);
    }