start Preview
Start the VisionSender thread to send all processor data to FtcDashboard/DS with dynamic switching. Without the preview active, the DS will display a raw unprocessed feed to save resources in Camera Stream, and FtcDashboard will be disabled. This is the default state of Vision. Activating this sender will set both FtcDashboard and the DS streams to be of a processor of your choosing, by changing a processor's name with setPreview() or via FtcDashboard.