public AbstractLoggingClientBuilder sampler(Sampler<? super ClientRequestContext> sampler) {
        requireNonNull(sampler, "sampler");
        successSampler = sampler;
        failureSampler = sampler;
        return this;
    }
Sets the {@link Sampler} that determines which request needs logging.
core/src/main/java/com/linecorp/armeria/client/logging/AbstractLoggingClientBuilder.java