@Override
    public int getType() {
        return DocumentProtocol.MESSAGE_REMOVEDOCUMENT;
    }
<p>When a visitor client receives a Remove as part of the visiting operation, this
timestamp represents the wall clock time in microseconds(*) of the tombstone's
creation (i.e. the highest known time the original document was removed).</p>

<p>If zero, the sending content node is too old to support this feature.</p>

<p>This value is not guaranteed to be linearizable. During e.g. network partitions this
value might not represent the latest acknowledged operation for the document.</p>

<p>Unsupported (and ignored) for Removes sent by the client during feeding.</p>

<p>(*) (wall clock seconds since UTC epoch * 1M) + synthetic intra-second microsecond counter.</p>
documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/RemoveDocumentMessage.java