code: function OAuth2Strategy (provider, client, verify) {
    Strategy.call(this)
    this.provider = provider
    this.endpoints = provider.endpoints
    this.mapping = provider.mapping
    this.client = client
    this.name = provider.id
    this.verify = verify
  }
docs: OAuth2Strategy
  
  Provider is an object defining the details of the authentication API.
  Client is an object containing provider registration info and options.
  Verify is the Passport callback to invoke after authenticating