code: private final String computeSigningCacheKeyName(AWSCredentials credentials,
              AWS4SignerRequestParams signerRequestParams) {
          final StringBuilder hashKeyBuilder = new StringBuilder(
                  credentials.getAWSSecretKey());
  
          return hashKeyBuilder.append("-")
                  .append(signerRequestParams.getRegionName())
                  .append("-")
                  .append(signerRequestParams.getServiceName()).toString();
      }
docs: Computes the name to be used to reference the signing key in the cache.