fatsify核心功能示例测试!!!

node_modules/pino/docs/asynchronous.md

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+# Asynchronous Logging
+
+Asynchronous logging enables the minimum overhead of Pino.
+Asynchronous logging works by buffering log messages and writing them in larger chunks.
+
+```js
+const pino = require('pino')
+const logger = pino(pino.destination({
+  dest: './my-file', // omit for stdout
+  minLength: 4096, // Buffer before writing
+  sync: false // Asynchronous logging
+}))
+```
+
+It's always possible to turn on synchronous logging by passing `sync: true`. 
+In this mode of operation, log messages are directly written to the
+output stream as the messages are generated with a _blocking_ operation.
+
+* See [`pino.destination`](/docs/api.md#pino-destination)
+* `pino.destination` is implemented on [`sonic-boom` ⇗](https://github.com/mcollina/sonic-boom).
+
+### AWS Lambda
+
+Asynchronous logging is disabled by default on AWS Lambda or any other environment
+that modifies `process.stdout`. If forcefully turned on, we recommend calling `dest.flushSync()` at the end
+of each function execution to avoid losing data.
+
+## Caveats
+
+Asynchronous logging has a couple of important caveats:
+
+* As opposed to the synchronous mode, there is not a one-to-one relationship between
+  calls to logging methods (e.g. `logger.info`) and writes to a log file
+* There is a possibility of the most recently buffered log messages being lost
+  in case of a system failure, e.g. a power cut.
+
+See also:
+
+* [`pino.destination` API](/docs/api.md#pino-destination)
+* [`destination` parameter](/docs/api.md#destination)