Use fillsinks_hybrid in FlowObject

This is otherwise identical to the implementation in GridObject, but
it also uses the queue array that it allocates as the heap for gwdt,
so it allocates the queue regardless of the value of hybrid.

src/topotoolbox/flow_object.py

@@ -16,7 +16,8 @@ class FlowObject():
     """
 
     def __init__(self, grid: GridObject,
-                 bc: np.ndarray | GridObject | None = None):
+                 bc: np.ndarray | GridObject | None = None,
+                 hybrid : bool = True):
         """The constructor for the FlowObject. Takes a GridObject as input,
         computes flow direction information and saves them as an FlowObject.
 
@@ -58,7 +59,11 @@ def __init__(self, grid: GridObject,
         if isinstance(bc, GridObject):
             bc = bc.z
 
-        _grid.fillsinks(filled_dem, dem, bc, dims)
+        queue = np.zeros_like(dem, dtype=np.int64, order='F')
+        if hybrid:
+            _grid.fillsinks_hybrid(filled_dem, queue, dem, bc, dims)
+        else:
+            _grid.fillsinks(filled_dem, dem, bc, dims)
 
         if restore_nans:
             dem[nans] = np.nan
@@ -73,7 +78,7 @@ def __init__(self, grid: GridObject,
 
         dist = np.zeros_like(flats, dtype=np.float32, order='F')
         prev = conncomps  # prev: dtype=np.int64
-        heap = np.zeros_like(flats, dtype=np.int64, order='F')
+        heap = queue      # heap: dtype=np.int64
         back = np.zeros_like(flats, dtype=np.int64, order='F')
         _grid.gwdt(dist, prev, costs, flats, heap, back, dims)