# Background Tasks { #background-tasks }

You can define background tasks to be run *after* returning a response.

This is useful for operations that need to happen after a request, but that the client doesn't really have to be waiting for the operation to complete before receiving the response.

This includes, for example:

* Email notifications sent after performing an action:

	}
	left, err := v.UnmarshalMsg(bts)
	if err != nil {
		t.Fatal(err)
	}
	if len(left) > 0 {
		t.Errorf("%d bytes left over after UnmarshalMsg(): %q", len(left), left)
	}

	left, err = msgp.Skip(bts)
	if err != nil {
		t.Fatal(err)
	}
	if len(left) > 0 {
		t.Errorf("%d bytes left over after Skip(): %q", len(left), left)
	}
}

func BenchmarkMarshalMsgnsScannerOptions(b *testing.B) {
	v := nsScannerOptions{}

  @SuppressWarnings("Immutable") // We don't modify this after construction.
  private final int[] rowCounts;

  @SuppressWarnings("Immutable") // We don't modify this after construction.
  private final int[] columnCounts;

  @SuppressWarnings("Immutable") // We don't modify this after construction.
  private final @Nullable V[][] values;

	if r.UnreadRune() == nil {
		t.Error("expected error after UnreadRune (1)")
	}
	// Test error after Read.
	_, _, err = r.ReadRune() // reset state
	if err != nil {
		t.Error("unexpected error on ReadRune (2):", err)
	}
	_, err = r.Read(buf)
	if err != nil {
		t.Error("unexpected error on Read (2):", err)
	}
	if r.UnreadRune() == nil {
		t.Error("expected error after Read (2)")
	}
	// Test error after ReadByte.

+ The PR title is formatted as follows: `net/http: frob the quux before blarfing`
  + The package name goes before the colon
  + The part after the colon uses the verb tense + phrase that completes the blank in,
    "This change modifies Go to ___________"
  + Lowercase verb after the colon
  + No trailing period
  + Keep the title as short as possible. ideally under 76 characters or shorter
+ No Markdown

import okio.Options
import okio.Source
import okio.Timeout
import okio.buffer

/**
 * Reads a stream of [RFC 2046][rfc_2046] multipart body parts. Callers read parts one-at-a-time
 * until [nextPart] returns null. After calling [nextPart] any preceding parts should not be read.
 *
 * Typical use loops over the parts in sequence:
 *
 * ```kotlin
 * val response: Response = call.execute()

        // Act
        blob.set(null);

        // Assert
        assertNotNull(blob.get(), "get() should return non-null after set(null)");
        assertEquals(0, blob.length(), "length() should be 0 after set(null)");
        assertEquals("", blob.toString(), "toString() should be empty after set(null)");
    }

    // Verifies constructor stores the exact array reference and exposes it via get()
    @Test

        // Call retainPayload and check if it becomes true
        message.retainPayload();
        assertTrue(message.isRetainPayload(), "isRetainPayload should be true after calling retainPayload");
    }

    @Test
    void testSetAndGetRawPayload() {
        // Initially, rawPayload should be null
        assertNull(message.getRawPayload(), "rawPayload should be null initially");

### 3.2 Automatic removal of noncurrent versions keeping only most recent ones after noncurrent days

It is possible to configure automatic removal of older noncurrent versions keeping only the most recent `N` using `NewerNoncurrentVersions`.

e.g, To remove noncurrent versions of all objects keeping the most recent 5 noncurrent versions under the prefix `user-uploads/` 30 days after they become noncurrent ,

```
{
    "Rules": [
        {

    assertThrows(NullPointerException.class, () -> getMap().putIfAbsent(null, v3()));
    expectUnchanged();
    expectNullKeyMissingWhenNullKeysUnsupported(
        "Should not contain null key after unsupported putIfAbsent(null, value)");
  }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_VALUES)
  public void testPutIfAbsent_nullValueUnsupported() {