presto-geospatial/src/main/java/io/prestosql/plugin/geospatial/GeoFunctions.java/GeoFunctions/stEnvelope
class GeoFunctions:    @Description("Returns the bounding rectangular polygon of a Geometry")
    @ScalarFunction("ST_Envelope")
    @SqlType(GEOMETRY_TYPE_NAME)
    public static Slice stEnvelope(@SqlType(GEOMETRY_TYPE_NAME) Slice input)
    {
        Envelope envelope = deserializeEnvelope(input);
        if (envelope == null) {
            return EMPTY_POLYGON;
        }
        return serialize(envelope);
    }