title: Does Google/Firebase android SDKs use GRPC?
body: <p>Recently I've been working on integrating a GRPC API in a <strong>size sensitive</strong> android app. The API only had a couple of Unary calls. I noticed that the resulting APK had <code>io.grpc</code> (613KB) &amp; <code>io.opencensus</code> (178.9KB) which was further reduced to 387.2KB and 39.4KB respectively using Proguard. I noticed that Proguard was able to remove many streaming call related classes/methods from the APK. However, I noticed that the app already had <code>com.google.protobuf</code> package, which I suspect is from something like Firebase SDK. </p>
  
  <p>If Firebase SDK imported <code>com.google.protobuf</code>, why didn't it need <code>io.grpc</code> for transport? Does it use something else? </p>