I started a thread by the same name in Racket-Users a couple days ago inquiring about the state of Structured Concurrency in Racket (and linked back to this forum for anyone there interested): https://groups.google.com/forum/#!topic/racket-users/XHm_1QFZPUI
From that thread it looks like Structured Concurrency hasn’t made it to the Racket world yet, but it’ll be interesting to see if/how that changes in the future.
Just wanted to link to it from here for anyone interested.