syntax_data: {"ast_node_type":"other","tokens":[{"end":83,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// lifetimes are related to the lifetime of the borrow on the closure made for
context_before:     /// This ensures that the `AsyncFn::call` will return a coroutine whose upvars'
context_after:     /// the call. This allows borrowck to enforce the self-borrows correctly.