Question: I'm getting the following warning reading a geojson with geopanda's read\_file():

```
...geodataframe.py:422: RuntimeWarning: Sequential read of iterator was interrupted. Resetting iterator. This can negatively impact the performance.
  for feature in features_lst:

```

Here's the code sample I used:

```
crime_gdf = gpd.read_file('datasets/crimes.geojson', bbox=bbox)

```

`crimes.geojson` is a file containing a large number of points, each with a 'Crime type'

`bbox` defines the boundaries

The code runs as expected, but I don't understand that warning.

**EDIT**

I converted the geojson to feather, and I get the same warning.

Answer: 
See my comment in Fiona's issue tracker: <https://github.com/Toblerity/Fiona/issues/986>

GDAL (the library Fiona uses to access the geodata) maintains an iterator over the features that are currently read. There a some operations that, for some drivers, can influence this iterator. Thus, after such operations we have to ensure that the iterator is set to the correct position that a continuous read of the data is ensured. Such operations include counting all features in a dataset, respectively calculating its extent.

There are different types of drivers in GDAL. Some drivers support random access, while some do not. For the drivers that do not support random access, the resetting of the iterator involves reading all features again up to the iterator position. As this is a possible costly operation, this RuntimeWarning is emitted, so that users are aware of this behavior.
I found this `fiona` PR that references the warning: <https://github.com/Toblerity/Fiona/pull/965>

I can reproduce the issue with `fiona` 1.8.18 when calling `list(src)` on a recently opened `Collection`, but not with 1.8.17. So I think this is a regression that was introduced in `fiona` 1.8.18, released on 2020-11-17.