### Installing xl-meta

To install, [Go](https://golang.org/dl/) must be installed. Once installed, execute this to install the binary:

```bash
go install github.com/minio/minio/docs/debugging/xl-meta@latest
```

### Using xl-meta

<p class="rule">
The completion of a single call of <code>f()</code> from <code>once.Do(f)</code>
is synchronized before the return of any call of <code>once.Do(f)</code>.
</p>

<p>
In this program:
</p>

<pre>
var a string
var once sync.Once

func setup() {
	a = "hello, world"
}

func doprint() {
	once.Do(setup)
	print(a)
}

func twoprint() {
	go doprint()

	ARCH=$(uname -m)
	case "${KNAME}" in
	SunOS)
		ARCH=$(isainfo -k)
		;;
	esac
}

## FIXME:
## In OSX, 'readlink -f' option does not exist, hence
## we have our own readlink -f behavior here.
## Once OSX has the option, below function is good enough.
##
## readlink() {
##     return /bin/readlink -f "$1"
## }
##
readlink() {
	TARGET_FILE=$1

	cd $(dirname $TARGET_FILE)

	if len(args.Resources) > maxDeleteList {
		return false, fmt.Errorf("internal error: localLocker.Lock called with more than %d resources", maxDeleteList)
	}

	// If we have too many waiting, reject this at once.
	if l.waitMutex.Load() > lockMutexWaitLimit {
		l.locksOverloaded.Add(1)
		return false, nil
	}
	// Wait for mutex
	defer l.getMutex()()
	if ctx.Err() != nil {
		return false, ctx.Err()
	}

       * timeoutFuture.setException() calls run(). That reentrancy would already be harmless, since
       * timeoutFuture can be set (and delegate cancelled) only once. (And "set only once" is
       * important for other reasons: run() can still be invoked concurrently in different threads,
       * even with the above null checks.)
       */
      timeoutFutureRef = null;

import java.lang.annotation.Retention;

import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Denotes that a bean should be created as a singleton instance.
 * <p>
 * Singleton-scoped beans are instantiated once and reused throughout the entire
 * Maven execution. This scope should be used for stateless services or components
 * that can be safely shared across the entire build process.
 * <p>
 * Example usage:
 * <pre>

          <defaultValue></defaultValue>
          <identifier>true</identifier>
        </field>
        <field>
          <name>extension</name>
          <version>1.1.0+</version>
          <type>String</type>
          <description>The file extension of the sub-artifact. Each classifier and extension pair may only appear once.</description>

	if w == nil { // when response recorder nil, this is an active request
		hstats.currentS3Requests.Inc(api)
		bh.httpStats[bucket] = hstats
		return
	} // else {
	hstats.currentS3Requests.Dec(api) // decrement this once we have the response recorder.

	hstats.totalS3Requests.Inc(api)
	code := w.StatusCode

	switch {
	case code == 0:
	case code == 499:
		// 499 is a good error, shall be counted as canceled.

        "network interceptor ${interceptors[index - 1]} must retain the same host and port"
      }
      check(calls == 1) {
        "network interceptor ${interceptors[index - 1]} must call proceed() exactly once"
      }
    }

    // Call the next interceptor in the chain.
    val next = copy(index = index + 1, request = request)
    val interceptor = interceptors[index]

    @Suppress("USELESS_ELVIS")

import java.util.logging.Logger;

import org.apache.commons.io.output.DeferredFileOutputStream;

/**
 * ContentOutputStream is a custom output stream that extends DeferredFileOutputStream.
 * It writes data to a temporary file once the data size exceeds a specified threshold.
 *
 * <p>This class ensures that the temporary file is deleted if it is not needed.
 * It uses a logger to log warnings if there are issues deleting the temporary file.</p>
 *