@Override
  public long getLong() {
    checkRefCount();
    int remaining = this.curItem.remaining();
    if (remaining >= Bytes.SIZEOF_LONG) {
      return this.curItem.getLong();
    }
    long l = 0;
    for (int i = 0; i < Bytes.SIZEOF_LONG; i++) {
      l <<= 8;
      l ^= get() & 0xFF;
    }
    return l;
  }
Returns the long value at the current position. Also advances the position by the size of long
@return the long value at the current position
hbase-common/src/main/java/org/apache/hadoop/hbase/nio/MultiByteBuff.java