Caused by: java.lang.UnsupportedOperationException
        at org.springframework.core.codec.AbstractDecoder.decodeToMono(AbstractDecoder.java:65)
        at org.springframework.http.codec.DecoderHttpMessageReader.readMono(DecoderHttpMessageReader.java:93)
        at org.springframework.http.codec.DecoderHttpMessageReader.readMono(DecoderHttpMessageReader.java:123)
        at org.springframework.web.reactive.result.method.annotation.AbstractMessageReaderArgumentResolver.readBody(AbstractMessageReaderArgumentResolver.java:172)
        at org.springframework.web.reactive.result.method.annotation.AbstractMessageReaderArgumentResolver.readBody(AbstractMessageReaderArgumentResolver.java:124)
        at org.springframework.web.reactive.result.method.annotation.RequestBodyArgumentResolver.resolveArgument(RequestBodyArgumentResolver.java:66)
        at org.springframework.web.reactive.result.method.InvocableHandlerMethod.resolveArg(InvocableHandlerMethod.java:214)
        ... 62 more