specifying expand_geometries = TRUE will expand individual GEOMETRYCOLLECTION
geometries to their own row in the resulting `sf` object. If the geometries are part
of a Feature (i.e., with properties), the properties will be repeated on each row.
The GEOMETRYCOLLECTION information is not kept when using expand_geometries = TRUE. Therefore,
it is not possible to reconstruct the GEOMETRYCOLLECTION after unnesting it.
Geojson specification RFC7946 https://tools.ietf.org/html/rfc7946#page-12
says all CRS should be the World Geodetic System 1984 (WGS 84) [WGS84] datum,
with longitude and latitude units of decimal degrees. This is equivalent to
the coordinate reference system identified by the Open Geospatial Consortium (OGC)
URN urn:ogc:def:crs:OGC::CRS84
geojson_sfc and geojson_sf automatically set the CRS to WGS 84.
The fields input and wkt let you to overwrite the defaults.