TIdBytes = TBytes;

TIdBytes is a type that represents a platform-agnostic representation for string data types. TIdBytes isolates the differences between a Delphi string and the .Net representation for string content. 

On the .Net platform, TIdBytes is declared as the TBytes data type. 

On the all other platforms, TIdBytes is declared an array of Byte data type. 

TIdBytes is the type used to represent parameter arguments for utility functions, like: 

TIdBytes is the type used to represent the return value from utility functions, like: