syntax_data: {"ast_node_type":"other","tokens":[{"end":79,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // (see src/libstd/sys/pal/unix/fast_thread_local.rs) that is currently
context_before:         // void register_callback(void (*fn)(void *), void *arg);
context_after:         // missing in illumos. For now at least, we must fallback to using