Yes you can use the LogMessageStreamer to do this, getting the first and the last features using Samplers.

What I do (using only a Creator, FeatureReaders and FeatureWriters) is adding DateTimeStampers and VariableSetters / VariableRetrievers to the begin and end of the workspace.

The LogMessageStreamer is probably a more elegant solution, but I'm not sure how it influences perfomance in big workspaces.

Added workspace demonstrating both methods.

Thank you, nielsgerrits !

For the sake of completion, there are a few other methods.

Firstly you could add a DateTimeStamper at the start and end of the translation. Obviously, it's not quite the same as the exact start/end time, but it could be close enough for your purposes.

Secondly, if you know any Python, you could use a Python startup script and a Python shutdown script to log the datetime. It would be a bit more accurate than the DateTimeStamper.

Finally, a Python shutdown script should also give you the elapsed time of a workspace. That should be fairly straightforward to do, even if you have minimal Python knowledge. I really thought it gave you the start/end time as well, although it's not in the documentation, so perhaps I was wrong.

Thank you Mark!