awaitNode property
The await site that produced this suspension, when there is one.
SCC40: this is what lets the resolved value be filed against its own await expression in AsyncExecutionState.resolvedAwaitResults instead of a single per-frame slot shared by every await in the statement. Null for suspensions the state machine raises itself (yield, await-for stream conversion), which resume by a different route and need no per-site replay.
Implementation
final SAstNode? awaitNode;