configure
Prepares the LINE SDK. Call once, as early as possible — App.onCreate and your iOS app's initialiser are both fine, and so is any shared startup code that runs before the first login.
Calling it again with an equal config is a no-op, so it is safe in code that may run more than once.
On Android the application Context is supplied automatically by an androidx.startup initialiser, so there is nothing platform-specific to pass. If your app removes that provider, use the Android-only configure(context, config) overload instead.
Throws
if called again with a different LineLoginConfig.channelId. iOS cannot honour it — the underlying SDK refuses to be set up twice — so failing loudly here beats behaving differently on each platform.