For now `xarray-safe-s1` cannot read tiff files through S3 access

[agrouaze]

Issue #23 is closed because we managed to read metadata (.xml files) through S3 protocol but currently the lecture of tiff files is done using rasterio and rasterio is not handling S3 access (except for AWS): rasterio/rasterio#3080

Using tifffile lib to access the SLC tiff file is for now impossible: cgohlke/tifffile#251 (comment)

Quick search on WWW, didn't allow me to find "on-the-shelves" solution (see also bopen/xarray-sentinel#141)