procedure AppendByteArray(var B1: TBytes; const B2: array of Byte);
var
  OldB1Len: Integer;
begin
  if Length(B2) = 0 then
    Exit;
  OldB1Len := Length(B1);
  SetLength(B1, OldB1Len + Length(B2));
  Move(B2[0], B1[OldB1Len], Length(B2));
end;
//delphi/2155