@Override
    public Mono<Void> setComplete() {
        return isCommitted() ? Mono.empty()
                             : doCommit(execute(() -> HttpRequest.of(headers.build())));
    }
Returns the {@link ClientRequestContext} associated with this request.
This method returns {@code null} until the request is sent.
A non-{@code null} value is available only after {@link #future()} is complete.
spring/spring6/src/main/java/com/linecorp/armeria/spring/internal/client/ArmeriaClientHttpRequest.java