public static Map<String, String> asMap(HttpRequestHeaders headers) {
    HashMap<String, String> map = new HashMap<>();
    if (headers == null) {
        return map;
    }
    for (Entry<String, String> entry : headers.entries()) {
        map.put(entry.getKey(), entry.getValue());
    }
    return map;
}
 

@NotNull
private static Map<String, String> headersToMap(@NotNull final HttpRequestHeaders headers) {
    final HashMap<String, String> map = Maps.newHashMap();
    for (Map.Entry<String, String> entry : headers.entries()) {
        map.put(entry.getKey(), entry.getValue());
    }
    return Collections.unmodifiableMap(map);
}
 

@Test
  public void testHttpHeaders() {
      HttpResourceGroup group = Ribbon.createHttpResourceGroupBuilder("test")
          .withHeader("header1", "group").build();
      
      HttpRequestTemplate<String> template = group.newTemplateBuilder("testHttpHeaders", String.class)
          .withUriTemplate("/foo/bar")
          .withMethod("GET")
          .withHeader("header2", "template")
          .withHeader("header1", "template").build();
      
      HttpRequestBuilder<String> requestBuilder = template.requestBuilder();
      requestBuilder.withHeader("header3", "builder").withHeader("header1", "builder");
HttpClientRequest<ByteBuf> request = requestBuilder.createClientRequest();
      HttpRequestHeaders headers = request.getHeaders();
      List<String> header1 = headers.getAll("header1");
      assertEquals(3, header1.size());
      assertEquals("group", header1.get(0));
      assertEquals("template", header1.get(1));
      assertEquals("builder", header1.get(2));
      List<String> header2 = headers.getAll("header2");
      assertEquals(1, header2.size());
      assertEquals("template", header2.get(0));
      List<String> header3 = headers.getAll("header3");
      assertEquals(1, header3.size());
      assertEquals("builder", header3.get(0));
  }
 

private void beforeRequest(String activityId, String uri, ResourceType resourceType, HttpRequestHeaders requestHeaders) {
    // TODO: perf counters
    // https://msdata.visualstudio.com/CosmosDB/_workitems/edit/258624
}
 

private static void addHeader(HttpRequestHeaders requestHeaders, String headerName, RxDocumentServiceRequest request) {
    String headerValue = request.getHeaders().get(headerName);
    if (!Strings.isNullOrEmpty(headerValue)) {
        requestHeaders.add(headerName, headerValue);
    }
}
 

private static void addHeader(HttpRequestHeaders requestHeaders, String headerName, String headerValue) {
    if (!Strings.isNullOrEmpty(headerValue)) {
        requestHeaders.add(headerName, headerValue);
    }
}