code: public String createAuthzHeaderForRequestTokenEndpoint(String callbackUrl, String endpointUrl) {
          Map<String, String> parameters = populateRequestTokenEndpointAuthzHeaderParams(callbackUrl);
          return signAndCreateAuthzHeader(endpointUrl, parameters);
      }
docs: Generates the Authorization header value required for a {@value TwitterConstants#TWITTER_ENDPOINT_REQUEST_TOKEN} endpoint
  request. See {@link https://dev.twitter.com/oauth/reference/post/oauth/request_token} for details.
  
  @param callbackUrl
  @param endpointUrl
  @return