The join strategy, represented by a value from the following list:
'auto' : The player will automatically join a cast session if one exists when play is called. Otherwise it will prompt the user with all available devices.
'manual' : The player will take over an existing session if there is one and the cast button is clicked. Otherwise it will prompt the user with all available devices.
'disabled' : The player is not affected by cast sessions and is not castable.
export declare type JoinStrategy = 'auto' | 'manual' | 'disabled';