private SSHPacket checkHeaderSpace(SSHPacket buffer) {
if (buffer.rpos() < 5) {
log.warn("Performance cost: when sending a packet, ensure that "
+ "5 bytes are available in front of the buffer");
SSHPacket nb = new SSHPacket(buffer.available() + 5);
nb.rpos(5);
nb.wpos(5);
nb.putBuffer(buffer);
buffer = nb;
}
return buffer;