Как получить параметр sql_variant для хранимой процедуры SQL CLR?

How can one add a sql_variant parameter to a SQL CLR stored procedure? Using System.Object does not work, and I don't see any attributes that I can use.

[Microsoft.SqlServer.Server.SqlProcedure]
public static void ClearOnePartition(
    SqlString aString
    , /* I want this to be a sql_variant */ object aVariant
)
{
    //do stuff here
}