trimStart method
Implementation
void trimStart(int count) {
if (count > _length) count = _length;
_startIndex += count;
_startIndex %= _array.length;
_length -= count;
}
void trimStart(int count) {
if (count > _length) count = _length;
_startIndex += count;
_startIndex %= _array.length;
_length -= count;
}