D is not really opinionated about concurrency and parallelism. It provides access to the OS mechanisms (pthreads). The standard library also has some task-based stuff. Then there are fibers (user-level threads), which vibed.org makes convenient to use. There is no definitive channel/queue mechanism provided by the standard library so far, but people have implemented them in libraries.

tl;dr: With D you use whatever is best for you.