}
final KeyHistogram histogram = new KeyHistogram(getTree(), start, end, sampleSize, keyDepth, treeDepth);
Buffer previousBuffer = null;
LevelCache lc = null;
Buffer buffer = null;
Direction direction = GTEQ;
if (start != null) {
start.copyTo(_key);
} else {
LEFT_GUARD_KEY.copyTo(_key);
direction = GT;