public Mono<Void> setComplete(@Nullable Throwable cause) {
        return !isCommitted() ? doCommit(null).then(Mono.defer(() -> cleanup(cause)))
                              : Mono.defer(() -> cleanup(cause));
    }
public Mono < Void > setComplete ( @ Nullable Throwable cause ) { return ! isCommitted ( ) ? doCommit ( null ) . then ( Mono . defer ( ( ) -> cleanup ( cause ) ) ) : Mono . defer ( ( ) -> cleanup ( cause ) ) ; }
Closes the {@link HttpResponseWriter} with the specified {@link Throwable} which is raised during
sending the response.