@Override
        public String toString() {
            return "SecurityStore(" +
                    "path=" + path +
                    ", modificationTime=" + (fileLastModifiedMs == null ? null : new Date(fileLastModifiedMs)) + ")";
        }
Loads this keystore
@return the keystore
@throws KafkaException if the file could not be read or if the keystore could not be loaded
  using the specified configs (e.g. if the password or keystore type is invalid)
clients/src/main/java/org/apache/kafka/common/security/ssl/DefaultSslEngineFactory.java