code: @NonNull
      @VisibleForTesting static Map<String, String> getHeaders(@NonNull AccessToken accessToken) {
          final String AUTH_HEADER = "Authorization";
          final String BEARER = "Bearer";
  
          Map<String, String> headers = new HashMap<String, String>();
          headers.put(AUTH_HEADER, BEARER + " " + accessToken.getToken());
          return headers;
      }
docs: Creates a {@link Map} of the headers needed to pass to the {@link WebView}.
  
  @param accessToken the {@link AccessToken} to use for the Authorization header.
  @return a {@link Map} containing headers to pass to {@link WebView}.