[Cyphase]

The client can constantly and at random intervals make lots of chaff queries to the API, so the service doesn't know which are real calls and which aren't. The client knows it's incoming calls history, so it can make sure it's chaff queries are statistically convincing.

For instance, if you often receive a call at the same time of day, that could be a detectable signal in the noise, unless the client then creates a lot of similar fake signals in the noise.