Android – How to replace the hamburger icon used for ActionBarToggle on Android Toolbar with a custom drawable

I have implemented a basic ActionBarDrawerToggle using the new Toolbar in Android 5.0.

However, I am unable to figure out how to change the default hamburger icon that is supplied.
From the android documentation it says that "the given Activity will be linked to the specified DrawerLayout and the Toolbar's navigation icon will be set to a custom drawable… This drawable shows a Hamburger icon when drawer is closed and an arrow when drawer is open. It animates between these two states as the drawer opens."

I currently have this all working correctly with the following code, however I want to replace the default supplied hamburger with my own drawable.

Here is my current code:

MainActivity.java

@InjectView(R.id.main_activity_toolbar)
Toolbar mToolbar;

@InjectView(R.id.main_activity_drawer_layout)
DrawerLayout mDrawerLayout;

@Override
protected void onCreate(Bundle savedInstanceState) {
    setContentView(R.layout.main_activity);
    super.onCreate(savedInstanceState);

    setSupportActionBar(mToolbar);
    mToolbar.setNavigationIcon(R.drawable.navigation);

    mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, mToolbar, R.string.drawer_open, R.string.drawer_close) {
        public void onDrawerClosed(View view) {
            super.onDrawerClosed(view);
            invalidateOptionsMenu();
        }

        public void onDrawerOpened(View drawerView) {
            super.onDrawerOpened(drawerView);
            invalidateOptionsMenu();
        }
    };

    mDrawerLayout.setDrawerListener(mDrawerToggle);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    getSupportActionBar().setHomeButtonEnabled(true);
}

This line:

mToolbar.setNavigationIcon(R.drawable.navigation);

doesn't seem to work.

Is this possible to do? Thanks!

ActionBarToggle Documentation – https://developer.android.com/reference/android/support/v7/app/ActionBarDrawerToggle.html