Using .length returns incorrect number of elements

[QueenSvetlana]

When using the .length property of a dynamic array why does it 
return the incorrect number of elements after I use the appender?

import std.stdio;
import std.array : appender;

void main()
{
     //declaring a dynamic array
     int [] arrayofNumbers;
     //append an element using the ~= syntax
     arrayofNumbers ~= 1;
     arrayofNumbers ~= 2;
     //print the array
     writeln(arrayofNumbers);

     //Using appender
     auto appendNumber = appender(arrayofNumbers);
     appendNumber.put(10);
     writeln(appendNumber.data);

     writeln(arrayofNumbers.length);

}

Output:

[1, 2]
[1, 2, 10]
2  --- > Should be 3