anchor.diff:      FCapacity :Integer;
       FBufferLocked:Boolean;
       FLineBreak: String;
  -    
  +
       procedure CheckNeedSize(pvSize: LongInt); overload;
       procedure CheckNeedSize(pvOffset, pvSize: LongInt); overload;
       function GetLength: Integer;
  
positive.code: begin
    FSize := 0;
    FPosition := 0;
    {$IFDEF MSWINDOWS}
    {$IFDEF DEBUG}
    ZeroMemory(@FData[0], FCapacity);
    {$ENDIF}
    {$ENDIF}
  end;
  
  function TDBufferBuilder.DecodeUTF8: string;
  
negative.code: procedure TDStringBuilder.Clear;
  begin
    FPosition := 0;
  
    // modify by ymf
    // 2017-01-10 17:36:13
    FCapacity := 0;
    SetLength(FData, 0);
  end;
  
  function TDStringBuilder.GetLength: Integer;
  