presto-parser/src/main/java/io/prestosql/sql/parser/AstBuilder.java/AstBuilder/visitExplain
class AstBuilder:    @Override
    public Node visitExplain(SqlBaseParser.ExplainContext context)
    {
        return new Explain(getLocation(context), context.ANALYZE() != null, context.VERBOSE() != null, (Statement) visit(context.statement()), visit(context.explainOption(), ExplainOption.class));
    }