order to better respond to customer support inquiries, it's often
helpful to know which of your users experienced a given crash.
Fortunately, Crashlytics makes this easy!
You can use
provide an id number, token, or hashed value that uniquely identifies
the end-user of your application without disclosing or transmitting any
of their personal information. This value is displayed right in the
void setUserIdentifier(String identifier);
If you would like to take advantage of advanced user identifier features, you can additionally use both:
void setUserName(String name);
void setUserEmail(String email);
For developers that want to take full advantage of our user feature set, using all three is recommended.