public static long toLong(ByteBuffer buffer, int offset) {
    return ConverterHolder.BEST_CONVERTER.toLong(buffer, offset);
  }
Reads a long value at the given buffer's offset.
@param buffer input byte buffer to read
@param offset input offset where Long is
@return long value at offset
hbase-common/src/main/java/org/apache/hadoop/hbase/util/ByteBufferUtils.java