In Symbian, the OS function to get the size of a pending datagram also
includes the size of the packet header (which is different for IPv4 and
IPv6). We were reading the datagram with the "peek" flag set to
implement pendingDatagramSize, then reading again normally when the
client called read/readDatagram.
This change removes the "peek" flag, and buffers the datagram in the
socket engine, returning it and clearing the buffer when read or
readDatagram is called.
If there is no buffered data, the existing code path is followed - it
isn't mandatory to call pendingDatagramSize before reading from the
socket.
Reviewed-by: Markus Goetz
(cherry picked from commit dd8de4c2437397748daba49569cbc7f89a8bfbee)
fe56131236