code: function OandaAdapter (config) {
  
      config.environment = config.environment || "practice";
  
      // this.accountId = accountId;
      this.accessToken = config.accessToken;
  
      this.restHost = environments[config.environment].restHost;
      this.streamHost = environments[config.environment].streamHost;
      this.secure = environments[config.environment].secure;
  
      if (config.environment === "sandbox") {
          this.username = config.username;
      }
  
      httpClient.setMaxSockets(maxSockets);
  
      this.subscriptions = {};
  
      this._eventsBuffer = [];
      this._pricesBuffer = [];
  
      this._sendRESTRequest = utils.rateLimit(this._sendRESTRequest, this, 1000 / maxRequestsPerSecond, maxRequestsWarningThreshold);
  }
docs: /*
  config.environment
  config.accessToken
  config.username (Sandbox only)