📝 Update More API Document

docs/api/text-callback-sink.md

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+---
+name: text-callback-sink
+group: api
+category: sink
+update-time: 20260520
+description: Create a callback sink that forwards rendered text using a TextFormatter.
+key-word:
+    - sink
+    - callback
+    - text
+    - public
+---
+
+## Text-callback-sink
+
+Create a callback sink that renders each record with a `TextFormatter` and forwards the resulting string to a callback. This is useful when integrations need formatted text without writing to the console directly.
+
+### Interface
+
+```moonbit
+pub fn text_callback_sink(
+  formatter : TextFormatter,
+  callback : (String) -> Unit,
+) -> FormattedCallbackSink {
+```
+
+#### input
+
+- `formatter : TextFormatter` - Formatter used to render each record.
+- `callback : (String) -> Unit` - Function receiving the rendered text.
+
+#### output
+
+- `FormattedCallbackSink` - Callback sink working on rendered text.
+
+### Explanation
+
+Detailed rules explaining key parameters and behaviors
+
+- This helper combines text rendering and callback delivery in one sink.
+- It is the text-oriented counterpart to `callback_sink(...)`.
+- Use it when a custom destination needs the final rendered text rather than the structured record object.
+
+### How to Use
+
+Here are some specific examples provided.
+
+#### When Need Rendered Text In A Custom Integration
+
+When a callback destination wants the final human-readable line:
+```moonbit
+let sink = text_callback_sink(
+  text_formatter(show_timestamp=false),
+  fn(line) {
+    println(line)
+  },
+)
+```
+
+In this example, the callback receives rendered text instead of a `Record`.
+
+### Error Case
+
+e.g.:
+- If structured field access is needed, use `callback_sink(...)` instead.
+
+- Callback failures are outside the sink's own API contract.
+
+### Notes
+
+1. This helper is useful for tests and adapters that want human-readable output.
+
+2. `formatted_callback_sink(...)` is the lower-level variant when the formatter input is already a `RecordFormatter`.