Getting the Position Stream from Geolocator into StreamBuilder Flutter - flutter

Question

I'm just starting with Flutter and very new to State/Stream/BloC concepts. I'm trying to update a FlutterMap center based on the coordinates from a Geolocator()'s Position stream. At the moment I'm just calling setState() updating a variable with the new value, but next I'll be trying using the Bloc pattern instead..
Now, as well as I set the center on the coordinates of the Position coming from the stream I also set a Marker on the same coordinates. I was expecting to see a Steady marker in the center of the screen and a moving map underneath but is the opposite.. the Map is steady and the Icon is moving.. Can you see where I got it wrong?
Also, for the stream: property of the StreamBuilder how would I get to pass the stream from Geolocator() as an event?
Many thanks for your time and help.
This is the Stream:
StreamSubscription positionStream = _geolocator
.getPositionStream(locationOptions)
.listen((Position position) {
setState(() {
_position = position;
});
print(
_position.latitude.toString() + ',' + _position.longitude.toString()); // ok
});
And this is the Map and the Marker:
Container(
height: 670,
width: 370,
child: FlutterMap(
options: MapOptions(
center: LatLng(_position.latitude, _position.longitude),
minZoom: 16.0,
maxZoom: 19.0,
),
layers: [
TileLayerOptions(
// urlTemplate:
// 'https://api.openrouteservice.org/mapsurfer/{z}/{x}/{y}.png?api_key=omitted',
urlTemplate:
'https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',
subdomains: ['a', 'b', 'c'],
keepBuffer: 20),
new MarkerLayerOptions(
markers: [
new Marker(
point: new LatLng(
_position.latitude, _position.longitude),
height: 200,
width: 200,
builder: (context) => IconButton(
icon: Icon(Icons.location_on),
color: Colors.red,
iconSize: 60,
onPressed: () {
print('icon tapped');
},
)),
],
),
],
),
),

Answer 1

Found the problem. I didn't assign any MapController().
So I created one and assign it to the FlutterMap. Inside the setState() I added _controller.move(LatLng(_position.latitude, _position.longitude), 16.0); and now the behaviour is the expected one. Steady Icon in the center of the screen and a moving map underneath.
Hope this will help others.
But still I will try to achieve the same with a BLoC pattern.
Cheers