Idl parsing not recognizing leading underscore for field names

line 94:9 token recognition error at: '_'

@Test
void testParsingLeadingUnderscore() throws IOException {
    String avdl = """
        @namespace("com.example.avro.schema")
        record Example {
            string _field;
        }
        """;

    var byteStream = new ByteArrayInputStream(avdl.getBytes(UTF_8));
    IdlFile parse = new IdlReader().parse(byteStream);
    Schema schema = parse.getNamedSchema("com.example.avro.schema.Example");
    // Fails since actual field name does not have a leading underscore
    assertEquals("_field", schema.getFields().get(0).name());
}