Detecting premature end of spawned threads with std.concurrency

[Matt Kline via Digitalmars-d-learn]

TDPL suggests that calls to std.concurrency.send will fail with 
an "OwnedTerminated" or "OwnedFailed" exception if the 
destination thread has exited, but neither the docs nor the 
current Phobos implementation make any mention of such 
exceptions. Thinking the information was just outdated, I 
searched the Git history of Phobos for such types, but found 
nothing.

What are current best practices for determining if a child thread 
has died? And should these types be added to TDPL errata?