return dstIndex - start;
        }

        /* The message provided to batch has a batchLimit that is
         * higher than the current batchLevel so we will now encode
         * that chained message. Before doing so we must increment
         * the batchLevel of the andx message in case it itself is an
         * andx message and needs to perform the same check as above.
         */

**FastAPI** provides the same `WebSocket` directly just as a convenience for you, the developer. But it comes directly from Starlette.

///

## Await for messages and send messages

In your WebSocket route you can `await` for messages and send messages.

```Python hl_lines="48-52"
{!../../docs_src/websockets/tutorial001.py!}
```

You can receive and send binary, text, and JSON data.

## Try it

                logger.debug("{}:{}", query, boost);
            }
            return convertBooleanQuery(context, booleanQuery, boost);
        }
        throw new InvalidQueryException(messages -> messages.addErrorsInvalidQueryUnknown(UserMessages.GLOBAL_PROPERTY_KEY),
                "Unknown q: " + query.getClass() + " => " + query);
    }

	}
	m.RecvSeq++
	return true
}

func (m *muxServer) message(msg message) {
	if debugPrint {
		fmt.Printf("muxServer: received message %d, length %d\n", msg.Seq, len(msg.Payload))
	}
	if !m.checkSeq(msg.Seq) {
		return
	}
	m.recvMu.Lock()
	defer m.recvMu.Unlock()
	if cap(m.inbound) == 0 {
		m.disconnect("did not expect inbound message", true)
		return
	}
	// Note, on EOF no value can be sent.

					case b, ok := <-in:
						if !ok {
							if got != messages {
								return NewRemoteErrf("wrong number of requests. want %d, got %d", messages, got)
							}
							return nil
						}
						out <- b
						got++
					}
				}
			},

			Subroute:    "some-subroute",
			OutCapacity: 1,
			InCapacity:  1, // Only one message buffered.
		}))
		errFatal(err)
	}

                .build());

        StringBuilder message = new StringBuilder("Messages [");
        boolean test = true;
        for (int i = 0; i < 999; i++) {
            boolean ok = output.containsKey("Progress (1): test-resource (" + i + "/999 B)");
            if (!ok) {
                System.out.println("false : " + i);
                message.append(i + ",");
            }
            test = test & ok;

        validateApi(body, messages -> {});
        if (body.documents == null) {
            throwValidationErrorApi(messages -> messages.addErrorsCrudFailedToCreateCrudTable(GLOBAL, "documents is required."));
        }
        if (body.documents.isEmpty()) {
            throwValidationErrorApi(messages -> messages.addErrorsCrudFailedToCreateCrudTable(GLOBAL, "documents is empty."));
        }

                throw new InvalidQueryException(messages -> messages.addErrorsInvalidQuerySortValue(UserMessages.GLOBAL_PROPERTY_KEY, text),
                        "Invalid sort field: " + termQuery);
            }
            final String sortField = values[0];
            if (!getQueryFieldConfig().isSortField(sortField)) {
                throw new InvalidQueryException(

                logger.debug("{}:{}", query, boost);
            }
            return convertWildcardQuery(context, wildcardQuery, boost);
        }
        throw new InvalidQueryException(messages -> messages.addErrorsInvalidQueryUnknown(UserMessages.GLOBAL_PROPERTY_KEY),
                "Unknown q: " + query.getClass() + " => " + query);
    }

Dans cet exemple, les messages seront écrits dans le fichier `log.txt` après que la réponse soit envoyée.

S'il y avait une `query` (paramètre nommé `q`) dans la requête, alors elle sera écrite dans `log.txt` via une tâche d'arrière-plan.

Et ensuite une autre tâche d'arrière-plan (générée dans les paramètres de la *la fonction de chemin*) écrira un message dans `log.txt` comprenant le paramètre de chemin `email`.