ot::Message::AppendBytes() method
Appends bytes to the end of the message. On success, this method grows the message by @p aLength bytes.
Arguments
aBuf
A pointer to a data buffer (MUST not be `nullptr`).
aLength
The number of bytes to append.
Return value
kErrorNone Successfully appended the bytes. kErrorNoBufs Insufficient available buffers to grow the message.