public static PayloadFormatter getPayloadFormat(String name) {
    PayloadFormatter formatter = mqttPayloadPluginMap.get(name);
    Preconditions.checkArgument(formatter != null, "Unknown payload format named: " + name);
    return formatter;
  }
PayloadFormatManager loads payload formatter from SPI services.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/protocol/mqtt/PayloadFormatManager.java