public static int prepend(IByteSequence src, int offset, int length, IUnit unit) {
int start = unit.start();
if (length > start) {
offset += length - start;
length = start;
}
start -= length;
unit.set(start, src, offset, offset + length);
unit.start(start);
unit.size(unit.size() + length);
return length;
}
