docs: @JRubyMethod(name="bufsize=")
          public static IRubyObject bufsize_set(IRubyObject self, IRubyObject size) {
          if(size.respondsTo("to_i")) {
              int n = RubyNumeric.fix2int(size.callMethod(self.getRuntime().getCurrentContext(), "to_i"));
              Parser p = (Parser)self.dataGetStructChecked();
              p.bufsize = n;
          }
          return self;
      }