title: Avro union field with "local-timestamp-millis" deserialization issue
body: <ul>
  <li>Avro: 10.1</li>
  <li>Dataflow (Apache Beam): 2.28.0</li>
  <li>Runner: org.apache.beam.runners.dataflow.DataflowRunner</li>
  </ul>
  <p>Avro schema piece:</p>
  <pre><code>{
    &quot;name&quot;: &quot;client_timestamp&quot;,
    &quot;type&quot;: [
      &quot;null&quot;,
      { &quot;type&quot;: &quot;long&quot;, &quot;logicalType&quot;: &quot;local-timestamp-millis&quot; }
    ],
    &quot;default&quot;: null,
    &quot;doc&quot;: &quot;Client side timestamp of this xxx&quot;
  },
  
  </code></pre>
  <p>An exception when writing Avro output file:</p>
  <pre><code>Caused by: org.apache.avro.UnresolvedUnionException: 
  Not in union [&quot;null&quot;,{&quot;type&quot;:&quot;long&quot;,&quot;logicalType&quot;:&quot;local-timestamp-millis&quot;}]: 
  2021-03-12T12:21:17.599
  </code></pre>
  <p><a href="https://gist.github.com/rulle-io/e833d8a9515508ee3ed35bd2df7ed840" rel="nofollow noreferrer">Link to a longer stacktrace</a></p>
  <p>Some of the steps taken:</p>
  <ul>
  <li>Replacing <code>&quot;logicalType&quot;:&quot;local-timestamp-millis&quot;</code> with <code>&quot;logicalType&quot;:&quot;timestamp-millis&quot;</code> causes the same error.</li>
  <li>Writing Avro locally also works.</li>
  <li>Removing <code>&quot;type&quot;: &quot;null&quot;</code> option eliminates the exception</li>
  </ul>