SendData
Posts a value into the client's DataMailer under dataKey, where a later CheckForReceivedData can pick it up — the mailer is a one-shot channel, so this is how a value is handed off to another screen. Sends data when it is non-null, otherwise incomingData. Dispatches onSuccess (no data) after the value is posted; onFailure (no data, error logged) when both data and incomingData are null, so there is nothing to send.
Parameters
Unique identifier of this event. Defaults to a random id.
Trigger that fires this event, built via EventTriggers.
Child events chained after this one, wired to its triggers (onSuccess, onFailure).
Mailer key the value is posted under, read by a matching CheckForReceivedData.
Literal value to send. Defaults to none (sends incomingData instead).