Properly close and join multiprocessing.Pool to avoid coverage issues.

Signed-off-by: Daniel Scheffler <danschef@gfz-potsdam.de>

sensormapgeo/transformer_3d.py

@@ -239,7 +239,10 @@ class SensorMapGeometryTransformer3D(object):
             #       arrays because this would allocate the memory for the input arrays of all bands at once.
             # NOTE: Use a multiprocessing imap iterator here when the OpenMP is finally fixed in the pyresample side:
             #       with multiprocessing.Pool(self.opts['nprocs']) as pool:
-            #           return [res for res in pool.imap_unordered(self._to_map_geometry_2D, args)]
+            #           res = [res for res in pool.imap_unordered(self._to_map_geometry_2D, args)]
+            #           pool.close()
+            #           pool.join()
+            #           return res
             try:
                 # this may cause a deadlock with the GNU OpenMP build, thus each WORKER has a timeout of 10 seconds
                 with ProcessPool() as pool:
@@ -328,6 +331,8 @@ class SensorMapGeometryTransformer3D(object):
             # NOTE: See the comments in the to_map_geometry() method.
             with multiprocessing.Pool(self.opts['nprocs']) as pool:
                 result = [res for res in pool.imap_unordered(self._to_sensor_geometry_2D, args)]
+                pool.close()
+                pool.join()
         else:
             result = [self._to_sensor_geometry_2D(argsdict) for argsdict in args]