Touch-tone buffer

From TeleFlow

Whenever a caller pushes a key/button on the phone, this generates a touch-tone. In TeleFlow, these touch-tones are accumulated in a buffer until a step that processes touch-tones is encountered. A given step may remove one, several, or all tones from the buffer. While the buffer has one or more touch-tone in it, TeleFlow will skip any Play or similar step unless the step is specifically set to be uninterruptible.