use ;
use StdioDiagLevel;
/// One line emitted by the runner on stderr.
///
/// Two variants:
///
/// - [`StdioError::Diag`] is per-request and carries `id`. It's the
/// normal channel for non-fatal warnings (e.g. transient
/// subprocess issues). The `id` is always the second field on the wire.
/// - [`StdioError::Fatal`] is process-level and carries no `id`. The
/// runner only emits one of these on its way to a non-zero exit
/// (import failure, asyncio init crash, etc.). Once the main loop
/// is running, no untagged stderr line is ever emitted.