code: public PactDslRequestWithPath headers(String firstHeaderName, String firstHeaderValue, String... headerNameValuePairs) {
          if (headerNameValuePairs.length % 2 != 0) {
              throw new IllegalArgumentException("Pair key value should be provided, but there is one key without value.");
          }
          requestHeaders.put(firstHeaderName, Collections.singletonList(firstHeaderValue));
  
          for (int i = 0; i < headerNameValuePairs.length; i+=2) {
            requestHeaders.put(headerNameValuePairs[i], Collections.singletonList(headerNameValuePairs[i+1]));
          }
  
          return this;
      }
docs: Headers to be included in the request
  
  @param firstHeaderName      The name of the first header
  @param firstHeaderValue     The value of the first header
  @param headerNameValuePairs Additional headers in name-value pairs.