Note that Signal's architecture makes this difficult. You can observe metadata going to the Signal server and going from either the Signal server or from Google

Note that Signal's architecture makes this difficult. You can observe metadata going to the Signal server and going from either the Signal server or from Google's blobs-to-apps service. Assuming that my phone uses the Google service (it can also use websockets directly from Signal), then you can see thee things: 1. You can see that my wife sends someone a message via Signal. 2. You can see a stream of data from Signal to Google. 3. You can see that an app on my phone receives a small amount of data from Google. You can still pick out something, but the architecture tilts the statistics and widens the error bars on your results.