@Nullable
    @Override
    public <T extends RequestContext> T push(RequestContext toPush) {
        requireNonNull(toPush, "toPush");
        if (sampler.isSampled(toPush)) {
            return delegate.push(wrapRequestContext(unwrapTraceableRequestContext(toPush)));
        }
        return delegate.push(toPush);
    }
Creates a new instance.

@param delegate the underlying {@link RequestContextStorage} that stores {@link RequestContext}
@param sampler the {@link Sampler} that determines whether to retain the stacktrace of the context leaks
core/src/main/java/com/linecorp/armeria/internal/common/LeakTracingRequestContextStorage.java