Firebase SDK social networking site authentication

As we have understood that popular social networking sites are Google Plus, Facebook, and Twitter, whereas GitHub is more of engineers' and software developers' place. Firebase can work with popular Authentication providers, and it can also support the non-popular authentication providers. We will explore popular authentication providers using the Firebase SDK. 

Google sign-in 

Google authentication will use the instance of the GoogleSigninOptions class and also it needs a googleApiClient object. Using a builder pattern, we will construct the following code snippet that will be passed to googleApiClient later:

GoogleSignInOptions signInOptions...