Since this thread was started, we actually included the _timestamp property by default in all examples in v1.11: https://prodi.gy/docs/changelog#v1.11.0 So you should be able to get the _timestamp of each individual example, and also the _session_id to map the examples to the respective session.
The timestamp is generated in JavaScript as follows: Math.floor(new Date().getTime() / 1000).