Async-logger-warn

Enqueue a warning-level record through the async logger. This is the convenience wrapper for log(Level::Warn, ...).

Interface

pub async fn[S] AsyncLogger::warn(
  self : AsyncLogger[S],
  message : String,
  fields~ : Array[@bitlogger.Field] = [],
) -> Unit {}

input

• self : AsyncLogger[S] - Async logger that should receive the warning record.
• message : String - Warning message text.
• fields : Array[Field] - Optional structured fields added to the record.

output

• Unit - No return value. The record is handled according to logger state and policy.

Explanation

Detailed rules explaining key parameters and behaviors

• This helper delegates to log(Level::Warn, ..., fields=fields).
• The record is still subject to min-level gating, patching, filtering, and overflow policy.
• This helper does not accept a per-call target override. It uses the logger's stored target unless the logger was derived earlier with with_target(...) or child(...).
• Warning records are useful for degraded but non-fatal runtime conditions.
• Use this helper when a named warning call is clearer than a raw log(...) call.

How to Use

Here are some specific examples provided.

When Need Async Degradation Signals

When the system should report a non-fatal problem:

logger.warn("retry budget running low")

In this example, the event is surfaced at warning severity without using the generic log(...) form.

When Attach Structured Warning Detail

When a warning event should include context:

logger.warn(
  "queue near capacity",
  fields=[@bitlogger.field("pending", logger.pending_count().to_string())],
)

In this example, the warning carries structured operational detail.

And any shared context already carried by the logger still participates ahead of these per-call fields when the record is built.

The write still uses the logger's stored target because this shortcut does not take a one-off target= override.

Error Case

e.g.:

• If the logger minimum level is above Warn, the record is skipped before enqueue.

• If the logger is closed or overflow policy prevents acceptance, the write may not become a normal queued record.

Notes

1. Use this helper for notable but non-fatal async runtime conditions.

2. Use log(...) instead when one warning call must override the target without deriving a new logger value.