public long getLastActivityTime() {
            return lastActivityTime;
        }

        public double getSuccessRate() {
            long total = successCount.get() + failureCount.get();
            return total > 0 ? (double) successCount.get() / total : 1.0;
        }
    }

    /**
     * Pool health metrics for monitoring
     */
    public static class PoolHealthMetrics {

    /**
     * Gets the number of chunks successfully written
     * @return the chunksWritten
     */
    public int getChunksWritten() {
        return this.chunksWritten;
    }

    /**
     * Gets the total number of bytes written in the copy operation
     * @return the totalBytesWritten
     */
    public int getTotalBytesWritten() {
        return this.totalBytesWritten;
    }

    /**
     * {@inheritDoc}

        @CsvSource({ "1048576, 524288, 8, 512, 4294967296, 2147483648", // 4GB total, 2GB free
                "2097152, 1048576, 8, 512, 8589934592, 4294967296", // 8GB total, 4GB free
                "134217728, 67108864, 8, 512, 549755813888, 274877906944", // 512GB total, 256GB free
                "1, 1, 1, 1, 1, 1", // Minimal values
                "0, 0, 1, 1, 0, 0" // Zero allocation units

            timeout=urllib3.Timeout.DEFAULT_TIMEOUT,
            maxsize=10,
            cert_reqs='CERT_NONE',
            ca_certs=ca_certs,
            retries=urllib3.Retry(
                total=5,
                backoff_factor=0.2,
                status_forcelist=[500, 502, 503, 504]
            )
        )

    def load(self):
        """
        Search for credentials with client_grants

     * Returns the similar document hash.
     *
     * @return The similar document hash.
     */
    public abstract String getSimilarDocHash();

    /**
     * Returns the track total hits.
     *
     * @return The track total hits.
     */
    public String getTrackTotalHits() {
        return null;
    }

    /**
     * Returns the min score.
     *
     * @return The min score.
     */

	// Completed size in bytes
	ReplicatedSize int64 `json:"completedReplicationSize"`
	// Failed size in bytes
	FailedSize int64 `json:"failedReplicationSize"`
	// Total number of failed operations
	FailedCount int64 `json:"failedReplicationCount"`
	// Total number of failed operations
	ReplicatedCount int64 `json:"replicationCount"`
	// Last bucket/object replicated.
	Bucket string `json:"bucket,omitempty"`

## Una aplicación con callbacks

Veamos todo esto con un ejemplo.

Imagina que desarrollas una aplicación que permite crear facturas.

Estas facturas tendrán un `id`, `title` (opcional), `customer`, y `total`.

El usuario de tu API (un desarrollador externo) creará una factura en tu API con un request POST.

Luego tu API (imaginemos):

* Enviará la factura a algún cliente del desarrollador externo.
* Recogerá el dinero.

import jcifs.internal.util.SMBUtil;

/**
 * Represents the FILE_FS_SIZE_INFORMATION structure used to query file system size information.
 * This structure provides details about the total allocation units, free allocation units,
 * sectors per allocation unit, and bytes per sector for a file system volume.
 */
public class FileFsSizeInformation implements AllocInfo {

		b.uint32(0)                      // number of the disk with the start of the central directory
		b.uint64(records)                // total number of entries in the central directory on this disk
		b.uint64(records)                // total number of entries in the central directory
		b.uint64(size)                   // size of the central directory

	Available  uint64 // in bytes
	MaxUsedPct int    // Used disk percentage of most filled disk, rounded down.
}

// TotalAvailable - total available space
func (p serverPoolsAvailableSpace) TotalAvailable() uint64 {
	total := uint64(0)
	for _, z := range p {
		total += z.Available
	}
	return total
}

// FilterMaxUsed will filter out any pools that has used percent bigger than max,