Entry point for initializing the Gravatar SDK.
The app name the SDK sends, in the X-Source header and at the head of userAgent, or null when there is none to send.
X-Source
The User-Agent the SDK sends, e.g. wp-android/27.6 GravatarAndroid/2.5.0.
wp-android/27.6 GravatarAndroid/2.5.0
Initializes the Gravatar SDK with the given API key.
Identifies the app calling the SDK, for the X-Source header and the User-Agent.
Initializes the Gravatar SDK with the given context. The context is used to get the application name and version, which identify the app in the X-Source header and the User-Agent of every request.