Java: ReflectData cannot resolve union with fixed

{
  "type" : "record",
  "name" : "simple_schema",
  "namespace" : "com.foo.bar",
  "fields" : [ {
    "name" : "foo",
    "type" : {
      "type" : "fixed",
      "name" : "bar",
      "size" : 2
    }
  }, {
    "name" : "baz",
    "type" : [ "null", "bar" ],
    "default" : null
  } ]
}