@Nullable
    static ClientRequestContext currentOrNull() {
        final RequestContext ctx = RequestContext.currentOrNull();
        if (ctx instanceof ClientRequestContext) {
            return (ClientRequestContext) ctx;
        }
        return null;
    }
Returns the client-side context of the {@link Request} that is being handled in the current thread.

@return the {@link ClientRequestContext} available in the current thread, or {@code null} if unavailable.
core/src/main/java/com/linecorp/armeria/client/ClientRequestContext.java