\brief Retrieve a Unified Symbol Resolution (USR) for the entity referenced
by the given cursor.
A Unified Symbol Resolution (USR) is a string that identifies a particular
entity (function, class, variable, etc.) within a program. USRs can be
compared across translation units to determine, e.g., when references in
one translation refer to an entity defined in another translation unit.
\brief Retrieve a Unified Symbol Resolution (USR) for the entity referenced by the given cursor.
A Unified Symbol Resolution (USR) is a string that identifies a particular entity (function, class, variable, etc.) within a program. USRs can be compared across translation units to determine, e.g., when references in one translation refer to an entity defined in another translation unit.