code: function dequeue(queue, item) {
      queue[SIZE] -= 1
  
      let done = false
      item.action(() => {
          if (done) {
              return
          }
          done = true
  
          if (item.next) {
              dequeue(queue, item.next)
          }
          else {
              assert(queue[TAIL] === item, "BROKEN")
              queue[TAIL] = null
          }
      })
  }
docs: Execute actions in series.
  
  @param {Queue} queue - The queue instance.
  @param {object} item - The queued item to be executed.
  @returns {void}