public static boolean isS3Request(RestRequest restRequest) {
    return restRequest != null && restRequest.getArgs().containsKey(S3_REQUEST);
  }
Determines if the input is a S3 API request
@param restRequest rest request
@return {@code true} if the request is a S3 API request.
ambry-api/src/main/java/com/github/ambry/rest/RestUtils.java