title: Firebase Analytics Filter By User ID
body: <p>The Firebase Android SDK for analytics provides a method named <code>setUserId(String id)</code>, now i enabled firebase logging and every time i called the method <code>setUserId(1234)</code> i see this in the logs <code>Setting user property (FE): _id, 1234</code>.</p>
  
  <p>My question is how come the Firebase dashboard does not let us filter by this property, there is no property not for userId and not _id, i even tried to add _id as a property in the dashboard but Firebase does not allow property names to start with an underscore.</p>
  
  <p>Do i really have to stop calling that method and just do <code>setUserProperty("userId", 1234)</code> or am i missing something...</p>