def offset_simple(offsets)
      raise ArgumentError.new("offsets should have ndims elements") unless offsets.size == ndims
      basic_offset_simple(@id, offsets.ffi_mem_pointer_hsize_t)
    end
def offset_simple(offsets)
      raise ArgumentError.new("offsets should have ndims elements") unless offsets.size == ndims
      basic_offset_simple(@id, offsets.ffi_mem_pointer_hsize_t)
    end
Set the offset of the dataspace. offsets should be an ndims-sized array
 of zero-based integer offsets.