code: function Trigger (opts) {
    opts = opts || {}
    if (!this.start || !this.stop) {
      throw new Error('start, stop are required members')
    }
    this.startDate = opts.startDate || new Date()
    this.endDate = opts.endDate || null
    this.stream = Observable.create(function (observer) { this.observer = observer }.bind(this))
  }
docs: var debug = require('debug')('cogsworth:Trigger') 
  Skeleton class/interface for triggers
  @param {*} opts