Converts a text string into a UTF-8 hex string and if the text input is already a hex string, also into text.
- requestType is hexConvert
- string is a text string, possibly a hex string
- binary (S) is the converted UTF-8 hex string
- text (S) is a text string converted from string if it is a valid UTF-8 hex string
- requestProcessingTime (N) is the API request processing time (in millisec)