code: function Flow(waits,    // @arg Integer: Number of wait for processes
                callback, // @arg Function/FunctionHash/Flow/FlowHash: callback and forks
                          //         callback on completion of processes.
                          //         callback(err:Error, args:MixArray)
                tag) {    // @arg String(= ""): tag name for Flow.dump()
                          // @desc: http://www.slideshare.net/uupaa/flowjs
      this._ = {
          missable: 0,        // Integer: Number of missable. default 0
          reason: "",         // String: exit or miss reason.
          waits:  waits,
          state:  PROGRESS,   // String: "progress", "done", "fail", "exit"
          name:   "",         // String: #fork(name)
          pass:   0,          // Integer: #pass() called
          miss:   0,          // Integer: #miss() called
          args:   [],         // MixArray: #pass(arg), #miss(arg) collections
          tag:    tag || "",
          fn:     callback
      };
      tag && (_progress[tag] = this); // register instance
      _updateState(this);
  }
docs: --- header ----------------------------------------------