syntax_data: {"ast_node_type":"other","tokens":[{"end":72,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// `UNRESUMED` (beginning of a coroutine) and `RETURNED`/`POISONED`
context_before:     /// Number of variants to reserve in coroutine state. Corresponds to
context_after:     /// (end of a coroutine) states.