addService (path, name, options) {
    const load = typeof path === 'string' || (_.isObject(path) && path.root && path.file)

    let proto = path
    if (load) {
      let protoFilePath = path
      const loadOptions = Object.assign({}, options)

      if (typeof path === 'object' && path.root && path.file) {
        protoFilePath = path.file
        if (!loadOptions.includeDirs) {
          // Support either multiple or single paths.
          loadOptions.includeDirs = Array.isArray(path.root) ? path.root : [path.root]
        }
      }

      const pd = protoLoader.loadSync(protoFilePath, loadOptions)
      proto = grpc.loadPackageDefinition(pd)
    }

    const data = mu.getServiceDefinitions(proto)

    if (!name) {
      name = Object.keys(data)
    } else if (typeof name === 'string') {
      name = [name]
    }

    for (const k in data) {
      const v = data[k]

      if (name.indexOf(k) >= 0 || name.indexOf(v.shortServiceName) >= 0) {
        v.middleware = []
        v.handlers = {}

        for (const method in v.methods) {
          v.handlers[method] = null
        }

        this.data[k] = v
      }
    }

    if (!this.name) {
      if (Array.isArray(name)) {
        this.name = name[0]
      }
    }
  }
Add the service and initialize the app with the proto.
Basically this can be used if you don't have the data at app construction time for some reason.
This is different than `grpc.Server.addService()`.
@param {String|Object} path - Path to the protocol buffer definition file
                             - Object specifying <code>root</code> directory and <code>file</code> to load
                             - Loaded grpc object
                             - The static service proto object itself
@param {Object} name - Optional name of the service or an array of names. Otherwise all services are used.
                     In case of proto path the name of the service as defined in the proto definition.
                     In case of proto object the name of the constructor.
@param {Object} options - Options to be passed to <code>grpc.load</code>