Library-async-logger-child

Create a child LibraryAsyncLogger[S] by composing the current target with another target segment. This is the library-facing hierarchical naming helper for async targets such as sdk.cache or plugin.worker.io.

Interface

pub fn[S] LibraryAsyncLogger::child(
  self : LibraryAsyncLogger[S],
  target : String,
) -> LibraryAsyncLogger[S] {

input

• self : LibraryAsyncLogger[S] - Parent facade whose target should be extended.
• target : String - Child target segment or suffix.

output

• LibraryAsyncLogger[S] - New library-facing async facade whose target is the composed child path.

Explanation

Detailed rules explaining key parameters and behaviors

• This API delegates to the wrapped async logger's child(...) behavior and then re-wraps the result as another LibraryAsyncLogger[S].
• If the parent target is empty, the child target becomes the full target.
• If the child target is empty, the parent target is preserved.
• If both are non-empty, they are joined with ..
• The original facade is not mutated. The returned facade stores the derived child target while the source facade keeps its previous parent target.
• Timestamp behavior, enabled-level gating, sink type, queue state, async config, and failure/lifecycle state remain the same because only the derived default target changes.
• Async state helpers remain hidden behind the narrower facade after rewrapping; use to_async_logger() if later code needs them.

How to Use

Here are some specific examples provided.

When Need Hierarchical Async Naming In A Library API

When a package wants stable namespace composition without exposing AsyncLogger[S]:

let worker = LibraryAsyncLogger::new(@bitlogger.console_sink())
  .with_target("plugin")
  .child("worker")

In this example, the final target becomes plugin.worker.

When Build Scoped Async Facades Step By Step

When deeper target composition should stay readable:

let client = LibraryAsyncLogger::new(@bitlogger.console_sink(), target="sdk")
  .child("http")
  .child("client")

In this example, the final facade emits under sdk.http.client.

And the target derivation does not rebuild or reset the wrapped async logger state.

The derived facade still uses the same timestamp and level-gating behavior as the source facade.

Error Case

e.g.:

• If target is empty, the returned facade keeps the original parent target.

• If callers need complete replacement instead of composition, with_target(...) should be used instead.

Notes

1. This is the preferred library-facing API for hierarchical async target naming.

2. Composition changes the target only and does not rebuild the queue or sink.

3. Use with_target(...) instead when the new target should replace the current target rather than extend it.