presto-postgresql/src/main/java/io/prestosql/plugin/postgresql/PostgreSqlClient.java/PostgreSqlClient/createJsonParser
class PostgreSqlClient:    private static JsonParser createJsonParser(Slice json)
            throws IOException
    {
        // Jackson tries to detect the character encoding automatically when using InputStream
        // so we pass an InputStreamReader instead.
        return JSON_FACTORY.createParser(new InputStreamReader(json.getInput(), UTF_8));
    }