code: function(callback) {
    tox.on('friendRequest', function(evt) {
      console.log('Accepting friend request from ' + evt.publicKeyHex());
      // Automatically accept the request
      tox.addFriendNoRequestAsync(evt.publicKey()).then(function() {
        console.log('Successfully accepted the friend request!');
      }).catch(function(err) {
        console.error('Couldn\'t accept the friend request:', err);
      });
    });
  
    tox.on('friendMessage', function(evt) {
      console.log('Message from friend ' + evt.friend() + ': ' + evt.message());
      // Echo message back to friend
      tox.sendMessageAsync(evt.friend(), evt.message()).then(function(receipt) {
        console.log('Echoed message back to friend, received receipt ' + receipt);
      }).catch(function(err) {
        console.error('Couldn\'t echo message back to friend:', err);
      });
    });
  
    // Setup friendMessage callback to listen for groupchat invite requests
    tox.on('friendMessage', function(evt) {
      if(evt.message() === 'invite text') {
        tox.inviteAsync(evt.friend(), groupchats['text']).then(function() {
          console.log('Invited ' + evt.friend() + ' to the text groupchat');
        });
      } else if(evt.message() === 'invite av') {
        tox.inviteAsync(evt.friend(), groupchats['av']).then(function() {
          console.log('Invited ' + evt.friend() + ' to the audio/video groupchat');
        });
      }
    });
  
    callback();
  }
docs: Initialize our callbacks, listening for friend requests and messages.