code: function (command, params, opts) {
          var self = this;
          this.cmd = spawn(command, params, opts);
  
          this.cmd.stdout.on('readable', function () {
              self.isSpawnReadable = true;
              privatePump.apply(self);
          });
          this.cmd.stdout.on('end', function () {
              self.push(null);
          });
          this.on('finish', function () {
              this.cmd.stdin.end();
          });
  
      }
docs: Spawn a process and set stdin to writable stream and stdout to readable stream.
  
  Please take a look at node.js-API for further information.
  
  @param {string} command - Command name that shoul be executed
  @param {string[]} [params] - Parameters to set in spawned process
  @param {{}} [opts] - Optional spawn settings