BitLogger/docs/api/callback-sink-type.md

name, group, category, update-time, description, key-word

name	group	category	update-time	description	key-word
callback-sink-type	api	sink	20260613	Public callback sink type used for forwarding structured records to user code.	sink callback type public

Callback-sink-type

CallbackSink is the public callback sink type used for forwarding structured Record values to user code. It is the concrete sink type returned by callback_sink(...) and is intended for tests, adapters, and custom integrations that want raw record access.

Interface

pub struct CallbackSink {
  callback : (Record) -> Unit
}

output

• CallbackSink - Public synchronous sink type that forwards full Record values to a stored callback.

Explanation

Detailed rules explaining key parameters and behaviors

• This is a public root struct, not a type alias.
• The current field is callback : (Record) -> Unit.
• callback_sink(...) constructs this type directly from a record callback.
• Unlike FormattedCallbackSink, this sink preserves full structured record access instead of converting records into text first.

How to Use

Here are some specific examples provided.

When Need A Typed Structured Callback Sink Value

When code should keep the concrete record-callback sink type visible:

let sink : CallbackSink = callback_sink(fn(rec) { println(rec.message) })

In this example, the sink value stays explicit and preserves direct access to structured record data.

When Need A Typed Callback-backed Logger

When logging should preserve the raw-record callback sink type in the logger:

let logger : Logger[CallbackSink] = Logger::new(callback_sink(fn(rec) { println(rec.target) }))

In this example, the concrete callback sink remains part of the logger type.

Error Case

e.g.:

• CallbackSink itself does not have a runtime failure mode.

• Behavior inside the stored callback is fully user-defined, so failures there are outside the sink type's own API contract.

Notes

1. Use callback_sink(...) when you need a value of this type.

2. Use FormattedCallbackSink when the destination expects final rendered text rather than full Record values.