function defineModel (context) {
  return Object.defineProperty(context, 'model', {
    get: modelGetter.bind(this),
    set: (value) => {
      if (!this.mntd || !this.debounceDelay) {
        return modelSetter.call(this, value)
      }
      this.dSet(modelSetter, [value], this.debounceDelay)
    },
    enumerable: true
  })
}
Defines the model used throughout the existing context.
@param {object} context