code: public static final ByteBuffer createReadCapacityMessage () {
  
          ByteBuffer cdb = ByteBuffer.allocate(DEFAULT_CDB_LENGTH);
          // operation code
          cdb.put(READ_CAPACITY_OP_CODE);
  
          cdb.rewind();
  
          return cdb;
      }
docs: Creates the Command Descriptor Block for a Read Capacity Message.
  
  @return A <code>ByteBuffer</code> object with the above data.