Calling Webclient API call(asynchronous) from mono core environment

can we use webclient API from in mono core environment?

For Example 

Func A()
{
    while(1)
    {
    ....
    // Call webclint API
        Client.getWebClient().post().uri(test\_uri)
                .header(HttpHeaders.CONTENT\_TYPE, MediaType.APPLICATION\_JSON\_VALUE)
                .body(Mono.just(record.value()), String.class)
                .accept(MediaType.APPLICATION\_JSON).exchangeToMono(response -> {

        if (response.statusCode().equals(HttpStatus.OK)) {
            logger.info("received 200 OK");
            return response.bodyToMono(String.class);
        } else if (response.statusCode().is4xxClientError()) {

            return response.createException().flatMap(Mono::error).onErrorReturn(
                    WebClientRequestException.class,
                    "4xx");
        } else if (response.statusCode().is5xxServerError()) {
            
            return response.createException().flatMap(Mono::error).onErrorReturn(
                    WebClientRequestException.class,
                    "5xx");
        }
        return null;
    }).onErrorMap(WebClientRequestException.class, throwable -> {
        return throwable;
    }).onErrorReturn(WebClientRequestException.class,
            "Unavailable")
    .subscribe();
    ....
    }
}

I am observing memory of applicatiion is increasing with every webclient API call. As per MAT, netty event poll handler is getting most the memory.

Could you please suggest anything?