squash: add a cloneWith method to add new items to a cloudevent

Signed-off-by: Lucas Holmquist <[email protected]>

Author: lholmquist

src/event/cloudevent.ts

@@ -100,6 +100,8 @@ export class CloudEvent implements CloudEventV1, CloudEventV03 {
     }
 
     this.validate();
+
+    Object.freeze(this);
   }
 
   get time(): string | Date {
@@ -167,4 +169,8 @@ export class CloudEvent implements CloudEventV1, CloudEventV03 {
       }
     }
   }
+
+  public cloneWith(options?: any): CloudEvent {
+    return new CloudEvent(Object.assign({}, this.toJSON(), options));
+  }
 }