title: dialogflow Error: 14 UNAVAILABLE: Getting metadata from plugin failed with error: Generator is already running
body: <p>I tested this code on my webOS emulator.
  webOS emulator uses nodejs version 6.0.0</p>
  
  <p>My code is here:</p>
  
  <pre><code>// The path to identify the agent that owns the created intent.
      const sessionPath = sessionClient.sessionPath(projectId, sessionId);
  
      let promise;
  
      for (const query of queries) {
          // The text query request.
          const request = {
                  session: sessionPath,
                  queryInput: {
                      text: {
                          text: query,
                          languageCode: languageCode,
                      },
                  },
          };
  
          if (!promise) {
              // LOOK: this code is executed
              promise = sessionClient.detectIntent(request);
          } else {
              // ....
          }
      }emphasized text
  
      promise
      .then(responses =&gt; {
          // ....
      })
      .catch(err =&gt; {
          // error has occurred after detectIntent() is called.
          console.log('ERROR: ' + err);
      });
  </code></pre>
  
  <p>Error message is here:
  Error: 14 UNAVAILABLE: Getting metadata from plugin failed with error: Generator is already running</p>
  
  <p>I don't know what this error means.
  I refered this code. but dialogflow does not work.
  <a href="https://github.com/googleapis/nodejs-dialogflow/blob/master/samples/detect.js" rel="nofollow noreferrer">https://github.com/googleapis/nodejs-dialogflow/blob/master/samples/detect.js</a></p>