code: public void start(@NonNull Activity activity, @NonNull String connection, @Nullable Map<String, Object> extraAuthParameters, @NonNull AuthCallback callback, int requestCode) {
          HashMap<String, Object> parameters;
          if (extraAuthParameters == null) {
              parameters = options.getAuthenticationParameters();
          } else {
              parameters = new HashMap<>(options.getAuthenticationParameters());
              parameters.putAll(extraAuthParameters);
          }
  
          WebAuthProvider.Builder builder = WebAuthProvider.init(options.getAccount())
                  .useBrowser(options.useBrowser())
                  .withParameters(parameters)
                  .withConnection(connection);
  
          final String connectionScope = options.getConnectionsScope().get(connection);
          if (connectionScope != null) {
              builder.withConnectionScope(connectionScope);
          }
          final String scope = options.getScope();
          if (scope != null) {
              builder.withScope(scope);
          }
          final String audience = options.getAudience();
          if (audience != null && options.getAccount().isOIDCConformant()) {
              builder.withAudience(audience);
          }
          final String scheme = options.getScheme();
          if (scheme != null) {
              builder.withScheme(scheme);
          }
          builder.start(activity, callback, requestCode);
      }
docs: Configures a new instance of the WebAuthProvider.Builder and starts it.
  
  @param activity            a valid Activity context
  @param connection          to use in the authentication
  @param extraAuthParameters extra authentication parameters to use along with the provided in the Options instance
  @param callback            to deliver the authentication result to
  @param requestCode         to use in the startActivityForResult request