This item is an integer identifier which, along with
              _array_data.array_id, should uniquely identify the
              particular block of array data.
              If _array_data.binary_id is not explicitly given,
              it defaults to 1.
              The value of _array_data.binary_id distinguishes
              among multiple sets of data with the same array
              structure.
              If the MIME header of the data array specifies a
              value for X-Binary-ID, the value of  _array_data.binary_id
              should be equal to the value given for X-Binary-ID.