procedure MyProc;
var
  LStrings: StringList;
begin
  LStrings.Add('test1');
  LStrings.Add('test2');
  Memo1.Lines.AddStrings(LStrings);
end;

(1) This implementation uses Delphi's Custom Managed Record class operators to Initialize, 
    Finalize, and Assign which were introduced in Delphi 10.4.
(1) The class operators Initialize() and Finalize() Create and Free the internal
    TStringlist. Each instance has its own unique internal TStringlist, 
    so no need for reference counting on the internal TStringlist.
    The class operator Assign() performs, A := B, and is the same as A.Assign(B).
(2) Implicits allow you to pass a StringList to TObject, TPersistent,
    TStrings, and TStringlist.

(1) When passing a StringList as a value parameter to a function, instead 
    of var or const, a new record gets created and all the strings are copied 
    to the new record's internal TStringlist, leaving the original param unchanged.
(2) CommaText property always uses StrictDelimiter = True (my own preference).
    Set to False or use DelimitedText property if you need StrictDelimer = False
(3) Some additional functions have been added, such as set functions, and more...

(1) This is based on Delphi's TStringlist implementation as of Delphi 12.
    If using with an older version of Delphi, you may need to remove refences
    to missing members that were not present in an ealier version of Delphi.

(2) Stringlist records can be "re-constructed"/reinitialized using:
      MyStrings := Stringlist.Default
        - Create a new default Stringlist
      MyStrings := Stringlist.Default(...)
        - Create a new Stringlist with specified properties (like TStringlist constructors)
      MyStrings := Stringlist.Default(Strings1)
        - Create a new Stringlist with same properties as Strings1.

WARNING, DO NOT USE:  MyStrings := Default(Stringlist);
  Default(T) is apparently not compatible with Custom Managed Records and
  causes a memory leak where MyStrings gets Initialized twice and finalized once
  and the original FData does not get freed.
  INSTEAD, use: MyStrings := Stringlist.Default;