setTwitterConsumerKeys method
if you will use twitter sign in method. you need to initialize consumer keys. https://developer.twitter.com/en
Implementation
void setTwitterConsumerKeys(String consumerKey, String consumerSecretKey) {
assert(consumerKey != null && consumerSecretKey != null);
this.consumerKey = consumerKey;
this.consumerSecretKey = consumerSecretKey;
}