Factor out distributed recursion

Author: gabotechs

src/common/mod.rs

@@ -2,6 +2,7 @@ mod children_helpers;
 mod map_last_stream;
 mod on_drop_stream;
 mod once_lock;
+mod recursion;
 mod task_context_helpers;
 mod time;
 mod uuid;
@@ -10,6 +11,7 @@ pub(crate) use children_helpers::require_one_child;
 pub(crate) use map_last_stream::map_last_stream;
 pub(crate) use on_drop_stream::on_drop_stream;
 pub(crate) use once_lock::OnceLockResult;
+pub(crate) use recursion::TreeNodeExt;
 pub(crate) use task_context_helpers::task_ctx_with_extension;
 pub(crate) use time::now_ns;
 pub(crate) use uuid::{deserialize_uuid, serialize_uuid};