**FastAPI** est totalement basé sur ces annotations de type, qui lui donnent de nombreux avantages.

Mais même si vous n'utilisez pas ou n'utiliserez jamais **FastAPI**, vous pourriez bénéficier d'apprendre quelques choses sur ces dernières.

/// note

Si vous êtes un expert Python, et que vous savez déjà **tout** sur les annotations de type, passez au chapitre suivant.

///

## Motivations

Prenons un exemple simple :

func (r *Record) Clone(dst sql.Record) sql.Record {
	other, ok := dst.(*Record)
	if !ok {
		other = &Record{}
	}
	other.object = r.object
	return other
}

// CloneTo clones the record to a json Record.
// Values are only unmashaled on object level.
func (r *Record) CloneTo(dst *json.Record) (sql.Record, error) {
	if dst == nil {
		dst = &json.Record{SelectFormat: sql.SelectFmtJSON}
	}

		// shutdown in progress
		return http.ErrServerClosed
	}

	// Close underneath HTTP listener.
	srv.listenerMutex.Lock()
	err := srv.listener.Close()
	srv.listenerMutex.Unlock()
	if err != nil {
		return err
	}

	// Wait for opened connection to be closed up to Shutdown timeout.
	return nil
}

// UseIdleTimeout configure idle connection timeout

// the upstream reader after close has been called.
type disconnectReader struct {
	r  io.Reader
	mu sync.Mutex
}

func (d *disconnectReader) Read(p []byte) (n int, err error) {
	d.mu.Lock()
	defer d.mu.Unlock()
	if d.r != nil {
		return d.r.Read(p)
	}
	return 0, errors.New("reader closed")
}

func (d *disconnectReader) Close() error {
	d.mu.Lock()
	d.r = nil

	}

	// Decrease reference count by 1.
	if err = rlk.Close(); err != nil {
		t.Fatal(err)
	}

	isClosed = rlk.IsClosed()
	if isClosed {
		t.Fatal("File ref count shouldn't be zero")
	}

	// Decrease reference count by 1.
	if err = rlk.Close(); err != nil {
		t.Fatal(err)
	}

	// Now file should be closed.
	isClosed = rlk.IsClosed()
	if !isClosed {

import java.io.InputStream;

/**
 * This inputstream ignores a close method.
 *
 * @author shinsuke
 *
 */
public class IgnoreCloseInputStream extends InputStream {

    private transient InputStream inputStream;

    public IgnoreCloseInputStream(final InputStream inputStream) {
        this.inputStream = inputStream;
    }

    @Override
    public void close() throws IOException {
        // inputStream.close();
    }

					return
				}
			}
		}
	}()
	// Close all active requests.
	if debugReqs {
		fmt.Println(c.String(), "Reconnected. Clearing outgoing.")
	}
	c.outgoing.Range(func(key uint64, client *muxClient) bool {
		client.close()
		return true
	})
	c.inStream.Range(func(key uint64, value *muxServer) bool {
		value.close()
		return true
	})

	c.inStream.Clear()
	c.outgoing.Clear()

  }

  /**
   * Returns the start position of the first occurrence of the specified {@code target} within
   * {@code array}, or {@code -1} if there is no such occurrence.
   *
   * <p>More formally, returns the lowest index {@code i} such that {@code Arrays.copyOfRange(array,
   * i, i + target.length)} contains exactly the same elements as {@code target}.
   *
   * @param array the array to search for the sequence {@code target}

            }
            off += r;
        }
        return off;
    }


    @Override
    public void close () throws IOException {
        super.close();
        try {
            this.handle.close();
        }
        finally {
            this.pipe.close();
        }
    }

	}
	defer done(0, &err)

	return p.storage.WalkDir(ctx, opts, wr)
}

// WalkDir will traverse a directory and return all entries found.
// On success a meta cache stream will be returned, that should be closed when done.
func (client *storageRESTClient) WalkDir(ctx context.Context, opts WalkDirOptions, wr io.Writer) error {
	// Ensure remote has the same disk ID.
	opts.DiskID = *client.diskID.Load()