docs: @Produces
      @LoggedIn
      public String extractUsername() {
  
          final KeycloakPrincipal principal = (KeycloakPrincipal) httpServletRequest.getUserPrincipal();
          if (principal != null) {
              logger.debug("Running with Keycloak context");
              KeycloakSecurityContext kcSecurityContext = principal.getKeycloakSecurityContext();
              return kcSecurityContext.getToken().getPreferredUsername();
          }
  
          logger.debug("Running outside of Keycloak context");
          final String basicUsername = HttpBasicHelper.extractUsernameAndPasswordFromBasicHeader(httpServletRequest)[0];
          if (! basicUsername.isEmpty()) {
              logger.debug("running HttpBasic auth");
              return basicUsername;
          }
  
          logger.debug("Running without any Auth context");
          return "admin"; // by default, we are admin!
      }