# File lib/codec/data.rb, line 66
      def initialize(capacity = 16)
        if capacity.is_a?(Integer)
          @impl = Cproton.pn_data(capacity.to_i)
          @free = true
        else
          # Assume non-integer capacity is a SWIG::pn_data_t*
          @impl = capacity
          @free = false
        end

        # destructor
        ObjectSpace.define_finalizer(self, self.class.finalize!(@impl, @free))
      end