public static boolean isPutOrPostS3RequestAndExpectContinue(RestRequest restRequest) {
    return CONTINUE.equals(restRequest.getArgs().get(EXPECT)) && (restRequest.getRestMethod().equals(RestMethod.PUT)
        || restRequest.getRestMethod().equals(RestMethod.POST)) && isS3Prefix(restRequest);
  }
Return true if the request set 100-continue in Except header and it's a S3 put request or S3 multi-upload post.
@param restRequest the {@link RestRequest}.
@return
ambry-api/src/main/java/com/github/ambry/rest/RestUtils.java