code: protected final void sendCrash(@Nullable String comment, @Nullable String userEmail) {
          new Thread(() -> {
              final CrashReportPersister persister = new CrashReportPersister();
              try {
                  if (ACRA.DEV_LOGGING) ACRA.log.d(LOG_TAG, "Add user comment to " + reportFile);
                  final CrashReportData crashData = persister.load(reportFile);
                  crashData.put(USER_COMMENT, comment == null ? "" : comment);
                  crashData.put(USER_EMAIL, userEmail == null ? "" : userEmail);
                  persister.store(crashData, reportFile);
              } catch (IOException | JSONException e) {
                  ACRA.log.w(LOG_TAG, "User comment not added: ", e);
              }
  
              // Start the report sending task
              new SchedulerStarter(this, config).scheduleReports(reportFile, false);
          }).start();
      }
docs: Send crash report given user's comment and email address.
  
  @param comment   Comment (may be null) provided by the user.
  @param userEmail Email address (may be null) provided by the client.