docs: public RequestSignerRegistry register(RequestSigner requestSigner, Class<? extends RequestSigner> signerType) {
          Map<Class<? extends RequestSigner>, RequestSigner> registeredSigners = new HashMap<>();
          registeredSigners.putAll(signerForType);
          registeredSigners.put(signerType, requestSigner);
          return new RequestSignerRegistry(registeredSigners);
      }