docs: function morph (value, input) {
    const result = input || readable()
    const cb = map[type(value)] || end
    cb(result, value)
    return new Proxy(result, {
      get(target, key, receiver) {
        if (key !== 'pipe') return target[key]
        return function (dest) {
          pump(result, dest)
          return dest
        }
      }
    })
  }