This class is designed as a "scratchpad" for generating many long arrays of unknown size. It will
never shrink its internal buffer, so it should be disposed as soon as it is no longer needed.
Usage Example:
LongArrayBuffer buf = new LongArrayBuffer();
List results = new ArrayList<>();
for (Object obj : listOfThingsToProcess) {
for (Object x : obj.thingsThatShouldBecomeLongs()) {
buf.add(someCalculation(x));
}
results.add(buf.toArray());
buf.clear();
}