It is just a standard function that can receive parameters.

It can be an `async def` or normal `def` function, **FastAPI** will know how to handle it correctly.

In this case, the task function will write to a file (simulating sending an email).

And as the write operation doesn't use `async` and `await`, we define the function with normal `def`:

{* ../../docs_src/background_tasks/tutorial001_py310.py hl[6:9] *}

	e.Encode(response)
	return bytesBuffer.Bytes()
}

// Write parts count
func setPartsCountHeaders(w http.ResponseWriter, objInfo ObjectInfo) {
	if strings.Contains(objInfo.ETag, "-") && len(objInfo.Parts) > 0 {
		w.Header()[xhttp.AmzMpPartsCount] = []string{strconv.Itoa(len(objInfo.Parts))}
	}
}

// Write object header

        byte[] hdr = new byte[64]; // SMB2 header is 64 bytes
        System.arraycopy(SMBUtil.SMB2_HEADER, 0, hdr, 0, 64);
        // Write Status (little-endian) at offset 8 in the SMB2 header
        SMBUtil.writeInt4(status, hdr, 8);
        // Write Command = SMB2_IOCTL (0x000B) at offset 12
        SMBUtil.writeInt2(0x000B, hdr, 12);
        // Mark as server response to be realistic (optional)

		var b Buffer
		b.Write(buf[0:1])
		for i := 0; i < 5<<10; i++ {
			b.Write(buf)
			b.Read(buf)
		}
	}
}

// Check that we don't compact too often. From Issue 5154.
func BenchmarkBufferFullSmallReads(b *testing.B) {
	buf := make([]byte, 1024)
	for i := 0; i < b.N; i++ {
		var b Buffer
		b.Write(buf)
		for b.Len()+20 < b.Cap() {
			b.Write(buf[:10])
		}

  fun connectionPreface() {
    withLock {
      if (closed) throw IOException("closed")
      if (!client) return // Nothing to write; servers don't send connection headers!
      if (logger.isLoggable(FINE)) {
        logger.fine(format(">> CONNECTION ${CONNECTION_PREFACE.hex()}"))
      }
      sink.write(CONNECTION_PREFACE)
      sink.flush()
    }
  }

  /** Applies `peerSettings` and then sends a settings ACK. */

        byte[] dst = new byte[2];

        // When
        int bytesWritten = trans.writeSetupWireFormat(dst, 0);

        // Then
        assertEquals(2, bytesWritten, "Should write 2 bytes.");
        assertEquals(SmbComTransaction.TRANS2_QUERY_PATH_INFORMATION, dst[0], "The first byte should be the subCommand.");
        assertEquals((byte) 0x00, dst[1], "The second byte should be 0.");
    }

    /**

    }

    @Test
    @DisplayName("writeSetupWireFormat writes the subCommand and a trailing 0")
    void testWriteSetupWireFormat() {
        Trans2QueryFSInformation cmd = new Trans2QueryFSInformation(5);
        byte[] buf = newBuffer(10);
        int written = cmd.writeSetupWireFormat(buf, 0);
        assertEquals(2, written, "setup packet should write 2 bytes");

        int dstIndex = 0;
        // The method should return 0 as it writes no parameter words
        int result = smbComNegotiate.writeParameterWordsWireFormat(dst, dstIndex);
        assertEquals(0, result, "writeParameterWordsWireFormat should return 0.");
    }

    /**
     * Test the writeBytesWireFormat method.
     * It should write the dialect string to the destination array.
     */
    @Test

        // Create a file larger than MAX_BUF_SIZE (10MB)
        // Write 11MB of data
        try (FileOutputStream fos = new FileOutputStream(largeFile)) {
            final byte[] chunk = new byte[1024 * 1024]; // 1MB
            for (int i = 0; i < 11; i++) { // Write 11MB
                fos.write(chunk);
            }
        }

        try {
            FileUtil.readBytes(largeFile);

   * segments, each governed by its own write lock. The segment lock is taken once for each explicit
   * write, and twice for each cache loading computation (once prior to loading the new value, and
   * once after loading completes). Much internal cache management is performed at the segment
   * granularity. For example, access queues and write queues are kept per segment when they are