syntax_data: {"ast_node_type":"other","tokens":[{"end":65,"kind":"keyword","start":0,"text":"profile_closures:"}]}
source_snippet:     profile_closures: bool = (false, parse_no_value, [UNTRACKED],
context_before:         "how to run proc-macro code (default: same-thread)"),
context_after:         "profile size of closures"),