TextMessage.toString() throws StringIndexOutOfBoundsException if payload contains multibyte characters

TextMessage.toStringPayload throws StringIndexOutOfBoundsException if a payload-bytes is greater than 10 and a payload-length less than 10.
This method throws an exception in the following code.

new TextMessage("\u3042\u3044\u3046\u3048\u304a").toString();

Stacktrace:
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 10
at java.lang.String.substring(String.java:1950)
at org.springframework.web.socket.TextMessage.toStringPayload(TextMessage.java:79)
at org.springframework.web.socket.AbstractWebSocketMessage.toString(AbstractWebSocketMessage.java:91)
at samples.websocket.config.SampleWebSocketsApplication.main(SampleWebSocketsApplication.java:58)

Pull request:
https://github.com/spring-projects/spring-framework/pull/657