5.16.2.2 Object(DN-String)
A value with the Object(DN-String) syntax is a UTF-8 string in the following format:
S:char_count:string_value:object_DN
where:
S is a string literal that MUST be present.
Each : is a string literal that MUST be present.
char_count is the number of characters in the string_value string.
object_DN is an object reference in the format of Object(DS-DN).