3.2.5.7 Receiving an $F Packet
The server MUST validate that the packet adheres to the syntax for $F (Filler) (section 2.2.3.5) packets.
If there are no bytes left to receive in the message body of the PushStart request, the server MUST send a PushStart response, as is specified in section 3.2.5.2.1.
Otherwise, the server MUST wait for a higher-layer triggered event or for a $C, $D, $E, or $F packet.
How to process a $C packet is specified in section 3.2.5.6. How to process a $D packet is specified in section 3.2.5.4. How to process an $E packet is specified in section 3.2.5.5.