Allocate a new Buffer with enough data to hold an RTP packet with csrc_count CSRCs, a payload
length of payload_len and padding of pad_len.
All other RTP header fields will be set to 0/FALSE.
| payload_len |
the length of the payload |
| pad_len |
the amount of padding |
| csrc_count |
the number of CSRC entries |
|
A newly allocated buffer that can hold an RTP packet with given parameters. |