Allows client to control what asset is played next in the stream. Useful for replaying assets or otherwise exerting more direct control over the content of the stream.
When this call is received the asset currently playing in the stream in question is faded out and the new one is played thereafter.
Parameters (some optional*):
Indicates which stream the operation should be performed on.
Indicates which asset should be played next.
OPTIONAL: adds a delay time (in ms) between when the previous asset fades out and the newly indicated asset begins playing. [this may not be functioning currently]
JSON response is success boolean, indicating that the operation was received by the server.