There is a way adding a NodeJS project to your configuration that will do a real time conversation using sockets. You can see this step by step setup instructions[1] on how to make an agent to human handoff using nodeJs. Also here is a video tutorial[2] using this github project.
[1]https://github.com/dialogflow/agent-human-handoff-nodejs#setup-instructions
[2]https://www.youtube.com/watch?v=EOAypIKmzyY