Rust and XML schema

example.xml

<ErrorRecovery>
  <ListID>1235623425</ListID>
  <EditSequence>whatever</EditSequence>
</ErrorRecovery>
<ErrorRecovery>
  <OwnerID>FOO</OwnerID>
</ErrorRecovery>
<ErrorRecovery>
  <TxnID>18302-1488303-random-numbers</TxnId>
  <TxnNumber>9492023</TxnNumber>
</ErrorRecovery>

some.xsd

<xsd:element name="ErrorRecovery">
	<xsd:complexType>
		<xsd:sequence>
			<xsd:choice>
				<xsd:element ref="ListID" minOccurs="0"/>
				<xsd:element ref="OwnerID" minOccurs="0"/>
				<xsd:element ref="TxnID" minOccurs="0"/>
			</xsd:choice>
			<xsd:element ref="TxnNumber" minOccurs="0"/>
			<xsd:element name="EditSequence" minOccurs="0">
				<xsd:simpleType>
					<xsd:restriction base="STRTYPE">
						<xsd:maxLength value="16"/>
					</xsd:restriction>
				</xsd:simpleType>
			</xsd:element>
			<xsd:element ref="ExternalGUID" minOccurs="0"/>
		</xsd:sequence>
	</xsd:complexType>
</xsd:element>

types.rs

#[derive(Debug, Deserialize)]
pub struct ErrorRecovery {
  pub _id: Option<ErrorRecoveryID>,
  
  pub txn_number: Option<i64>,
  pub edit_sequence: Option<String>,
  
  #[serde(rename = "ExternalGUID")]
  pub external_guid: Option<String>,
}

#[derive(Debug, Deserialize)]
pub enum ErrorRecoveryId {
  ListID(String),
  OwnerID(String),
  TxnID(String),
}