* runs quickly, since the row key is provided. However, {@code column(columnKey).size()} takes
   * longer, since an iteration across all row keys occurs.
   *
   * <p>Note that this implementation is not synchronized. If multiple threads access this table
   * concurrently and one of the threads modifies the table, it must be synchronized externally.
   *

</p>
<ul>
	<li>a <a href="#Constants">constant</a> index must be in range</li>
	<li>if <code>x</code> is out of range at run time,
	    a <a href="#Run_time_panics">run-time panic</a> occurs</li>
	<li><code>a[x]</code> is the array element at index <code>x</code> and the type of
	    <code>a[x]</code> is the element type of <code>A</code></li>
</ul>

<p>

 *
 * This class is tolerant of some I/O errors. If files are missing from the filesystem, the
 * corresponding entries will be dropped from the cache. If an error occurs while writing a cache
 * value, the edit will fail silently. Callers should handle other problems by catching
 * `IOException` and responding appropriately.
 *

}

// Transaction start a transaction as a block, return error will rollback, otherwise to commit. Transaction executes an
// arbitrary number of commands in fc within a transaction. On success the changes are committed; if an error occurs
// they are rolled back.
func (db *DB) Transaction(fc func(tx *DB) error, opts ...*sql.TxOptions) (err error) {
	panicked := true

	if committer, ok := db.Statement.ConnPool.(TxCommitter); ok && committer != nil {

			readBytes, _ := buf.Read(tmp)
			yBytes := Repeat(y, growLen)
			allocs := testing.AllocsPerRun(100, func() {
				buf.Grow(growLen)
				buf.Write(yBytes)
			})
			// Check no allocation occurs in write, as long as we're single-threaded.
			if allocs != 0 {
				t.Errorf("allocation occurred during write")
			}
			// Check that buffer has correct data.

	f.formatOctal(v7.gid(), 0)
	f.formatOctal(v7.size(), int64(len(data))) // Must be < 8GiB
	f.formatOctal(v7.modTime(), 0)
	tw.blk.setFormat(format)
	if f.err != nil {
		return f.err // Only occurs if size condition is violated
	}

	// Write the header and data.
	if err := tw.writeRawHeader(&tw.blk, int64(len(data)), flag); err != nil {
		return err
	}
	_, err := io.WriteString(tw, data)
	return err

   * implementation; otherwise refreshes will be performed during unrelated cache read and write
   * operations.
   *
   * <p>Currently automatic refreshes are performed when the first stale request for an entry
   * occurs. The request triggering refresh will make a synchronous call to {@link
   * CacheLoader#reload}
   * to obtain a future of the new value. If the returned future is already complete, it is returned

func (client *peerRESTClient) Trace(ctx context.Context, traceCh chan<- []byte, traceOpts madmin.ServiceTraceOpts) {
	go func() {
		for {
			// Blocks until context is canceled or an error occurs.
			client.doTrace(ctx, traceCh, traceOpts)
			select {
			case <-ctx.Done():
				return
			default:
				// There was error in the REST request, retry after sometime as probably the peer is down.

 *
 * <p><strong>Cycle Detection</strong>
 *
 * <p>Deadlocks can arise when locks are acquired in an order that forms a cycle. In a simple
 * example involving two locks and two threads, deadlock occurs when one thread acquires Lock A, and
 * then Lock B, while another thread acquires Lock B, and then Lock A:
 *
 * <pre>
 * Thread1: acquire(LockA) --X acquire(LockB)
 * Thread2: acquire(LockB) --X acquire(LockA)
 * </pre>

				internalLogIf(ctx, err)
			}
			if retries >= maxTries {
				return err
			}
			retries++
			time.Sleep(retryDelay)
		}
		return nil
	})

	// Blocks while consuming entries or an error occurs.
	err = bw.Close()
	if err != nil {
		mc.setErr(err.Error())
	}
	metaMu.Lock()
	defer metaMu.Unlock()
	if mc.meta.error != "" {
		return err
	}
	// Save success