Q:

The initial activity in Google Sign takes an excessive time

I've integrated Google sign in into my app,however for some reason the initial screen took forever to load (about 10 secs!). I've figured out that even when it comes to the simplest Google sign-in code main activity takes about 10 secs to load- I've tried two different repos:
Google's https://github.com/googlesamples/google-services.git
and this one too: https://github.com/AleBarreto/SimpleLoginLibrary
For both, main activity doesn't access network or disk and yet something delays it by about 10 seconds. I've tried two different physical devices,as well as AVDs.
From what I can see, the app is always delayed before onCreate(!) so it's not about the code. The only thing there is in common is that I've created a google-services.json file for each of them :P 

A:

Are you using Instant Run feature in Android Studio? From what I've experienced using Instant Run causes extra delay on starting app like you have mentioned. Try disabling it from Android Studio Settings->Build, Execution, Deployment -> Untick Enable Instant Run. 
Note: Instant Run is enabled by default.

