{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[48:55] hl[51:52,54] *}

### Чтение одного героя { #read-one-hero }

Мы можем **прочитать** одного `Hero`.

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[58:63] hl[60] *}

### Удаление героя { #delete-a-hero }

Мы также можем **удалить** `Hero`.

		}
	} else {
		copy(r.buf[r.w:], p)
		r.w += n
	}

	if r.w == r.size {
		r.w = 0
	}
	if r.w == r.r {
		r.isFull = true
	}

	return n, err
}

// WriteByte writes one byte into buffer, and returns ErrIsFull if buffer is full.
func (r *RingBuffer) WriteByte(c byte) error {
	r.mu.Lock()
	defer r.mu.Unlock()
	if err := r.err; err != nil {
		if err == io.EOF {
			err = ErrWriteOnClosed

0002 0.554 callEnd
0001 0.624 responseBodyEnd
0001 0.624 connectionReleased
0001 0.624 callEnd
```

The `EventListener.Factory` also makes it possible to limit metrics to a subset of calls. This one captures metrics on a random 10%:

```java
class MetricsEventListener extends EventListener {
  private static final Factory FACTORY = new Factory() {
    @Override public EventListener create(Call call) {

    // in our test environment, which foils the purpose of this test, so we disable the logic for
    // our test by setting a static field. We are changing the field in the parallel version of FRQ
    // and each test creates its own one of those, so there is no test interference here.
    Class<?> sepFrqSystemLoaderC =
        sepLoader.loadClass(FinalizableReferenceQueue.SystemLoader.class.getName());

import java.util.Iterator;
import java.util.Objects;
import org.jspecify.annotations.Nullable;

/**
 * A collection which forwards all its method calls to another collection. Subclasses should
 * override one or more methods to modify the behavior of the backing collection as desired per the
 * <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *

      /*
       * If isDone is true during the call to listenInPoolThread,
       * listenInPoolThread doesn't start a thread. Make sure it's false the
       * first time through (and forever after, since no one else cares about
       * it).
       */
      return false;
    }
  }

  private static final class RecordingRunnable implements Runnable {
    final CountDownLatch wasRun = new CountDownLatch(1);

import java.util.Iterator;
import java.util.Objects;
import org.jspecify.annotations.Nullable;

/**
 * A collection which forwards all its method calls to another collection. Subclasses should
 * override one or more methods to modify the behavior of the backing collection as desired per the
 * <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *

import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import org.jspecify.annotations.Nullable;

/**
 * A list which forwards all its method calls to another list. Subclasses should override one or
 * more methods to modify the behavior of the backing list as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *

.screenshot:before {
  content: '';
  position: absolute;
  top: 15px;
  left: 15px;
  display: inline-block;
  width: 15px;
  height: 15px;
  border-radius: 50%;
  /* A little hack to display the window buttons in one pseudo element. */
  background: #d9515d;
  -webkit-box-shadow: 25px 0 0 #f4c025, 50px 0 0 #3ec930;
          box-shadow: 25px 0 0 #f4c025, 50px 0 0 #3ec930;
}

.doc-param-details .highlight {
  overflow-x: auto;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.concurrent.atomic.AtomicLong;

/**
 * One or more variables that together maintain an initially zero {@code long} sum. When updates
 * (method {@link #add}) are contended across threads, the set of variables may grow dynamically to