function getProjectionIdentifier(projection) {
  const ogcId = 'http://www.opengis.net/def/crs/';
  const code = projection.getCode();
  if (code.startsWith(ogcId)) {
    return code;
  }
  if (code.startsWith('EPSG:')) {
    return `${ogcId}EPSG/0/${code.slice(5)}`;
  }
  if (equivalentProjections(projection, getProjection('EPSG:4326'))) {
    return `${ogcId}EPSG/0/4326`;
  }

  // hope for the best
  return code;
}
Gets a CRS identifier accepted by Sentinel Hub.
See https://docs.sentinel-hub.com/api/latest/api/process/crs/.

@param {import("../proj/Projection.js").default} projection The projection.
@return {string} The projection identifier accepted by Sentinel Hub.