📝 Document logger config presets

docs/api/with-queue.md

@@ -0,0 +1,76 @@
+---
+name: with-queue
+group: api
+category: config
+update-time: 20260520
+description: Add a queue wrapper to an existing logger config preset.
+key-word:
+    - preset
+    - queue
+    - config
+    - public
+---
+
+## With-queue
+
+Add a synchronous queue wrapper to an existing `LoggerConfig`. This preset helper is the config-side counterpart to `Logger::with_queue(...)`, allowing queue behavior to be expressed before the runtime logger is built.
+
+### Interface
+
+```moonbit
+pub fn with_queue(
+  config : LoggerConfig,
+  max_pending~ : Int = 0,
+  overflow~ : QueueOverflowPolicy = QueueOverflowPolicy::DropNewest,
+) -> LoggerConfig {
+```
+
+#### input
+
+- `config : LoggerConfig` - Base logger config to wrap.
+- `max_pending : Int` - Maximum number of pending records allowed in the queue.
+- `overflow : QueueOverflowPolicy` - Overflow behavior such as `DropNewest` or `DropOldest`.
+
+#### output
+
+- `LoggerConfig` - A copy of the input config with `queue=Some(QueueConfig::new(...))`.
+
+### Explanation
+
+Detailed rules explaining key parameters and behaviors
+
+- This helper preserves the original config's `min_level`, `target`, `timestamp`, and `sink` fields.
+- Only the top-level `queue` field is added or replaced.
+- The helper can be composed with any preset, including `console(...)`, `json_console(...)`, `text_console(...)`, and `file(...)`.
+
+### How to Use
+
+Here are some specific examples provided.
+
+#### When Need Config-side Queueing
+
+When queue behavior should be configured before calling `build_logger(...)`:
+```moonbit
+let config = with_queue(
+  text_console(target="svc"),
+  max_pending=32,
+  overflow=QueueOverflowPolicy::DropOldest,
+)
+```
+
+In this example, the text console preset is wrapped with a bounded queue config.
+
+And sink-specific settings remain unchanged.
+
+### Error Case
+
+e.g.:
+- If `max_pending` is too small, burst traffic may trigger overflow handling sooner.
+
+- If the wrapped runtime logger is never flushed or drained, queued records may remain pending depending on how the built sink is used.
+
+### Notes
+
+1. This helper is config composition only; it does not build or run the logger.
+
+2. Queue wrapping can be combined with `with_file_rotation(...)` when the base config is file-based.