Parse successful
<?xml version="1.0" encoding="ISO-8859-1"?>
<Dataset xmlns="http://xml.opendap.org/ns/DAP/4.0#" xml:base="file:dap4/test_simple_6.3.xml" dapVersion="4.0" dmrVersion="1.0" name="test_simple_6.3">
    <Structure name="s">
        <Int32 name="i1"/>
        <String name="s"/>
        <Structure name="inner"/>
    </Structure>
</Dataset>

<?xml version="1.0" encoding="ISO-8859-1"?>
<Dataset xmlns="http://xml.opendap.org/ns/DAP/4.0#" xml:base="file:dap4/test_simple_6.3.xml" dapVersion="4.0" dmrVersion="1.0" name="test_simple_6.3">
    <Structure name="s">
        <Int32 name="i1"/>
        <String name="s"/>
        <Structure name="inner"/>
        <Attribute name="DAP4_Checksum_CRC32" type="String">
            <Value>196bdc9a</Value>
        </Attribute>
    </Structure>
</Dataset>

The data:
{ { 123456789, "Silly test string: 1", {  } } }