public final OperationFuture<ExternalAccessRule, OperationMetadata> createExternalAccessRuleAsync(
      NetworkPolicyName parent,
      ExternalAccessRule externalAccessRule,
      String externalAccessRuleId) {
    CreateExternalAccessRuleRequest request =
        CreateExternalAccessRuleRequest.newBuilder()
            .setParent(parent == null ? null : parent.toString())
            .setExternalAccessRule(externalAccessRule)
            .setExternalAccessRuleId(externalAccessRuleId)
            .build();
    return createExternalAccessRuleAsync(request);
  }
Creates a new external access rule in a given network policy.

<p>Sample code:

<pre>{@code
// This snippet has been automatically generated and should be regarded as a code template only.
// It will require modifications to work:
// - It may require correct/in-range values for request initialization.
// - It may require specifying regional endpoints when creating the service client as shown in
// https://cloud.google.com/java/docs/setup#configure_endpoints_for_the_client_library
try (VmwareEngineClient vmwareEngineClient = VmwareEngineClient.create()) {
  NetworkPolicyName parent =
      NetworkPolicyName.of("[PROJECT]", "[LOCATION]", "[NETWORK_POLICY]");
  ExternalAccessRule externalAccessRule = ExternalAccessRule.newBuilder().build();
  String externalAccessRuleId = "externalAccessRuleId1937389350";
  ExternalAccessRule response =
      vmwareEngineClient
          .createExternalAccessRuleAsync(parent, externalAccessRule, externalAccessRuleId)
          .get();
}
}</pre>

@param parent Required. The resource name of the network policy to create a new external access
    firewall rule in. Resource names are schemeless URIs that follow the conventions in
    https://cloud.google.com/apis/design/resource_names. For example:
    `projects/my-project/locations/us-central1/networkPolicies/my-policy`
@param externalAccessRule Required. The initial description of a new external access rule.
@param externalAccessRuleId Required. The user-provided identifier of the `ExternalAccessRule`
    to be created. This identifier must be unique among `ExternalAccessRule` resources within
    the parent and becomes the final token in the name URI. The identifier must meet the
    following requirements:
    <ul>
      <li>Only contains 1-63 alphanumeric characters and hyphens
      <li>Begins with an alphabetical character
      <li>Ends with a non-hyphen character
      <li>Not formatted as a UUID
      <li>Complies with [RFC 1034](https://datatracker.ietf.org/doc/html/rfc1034) (section 3.5)
    </ul>

@throws com.google.api.gax.rpc.ApiException if the remote call fails
java-vmwareengine/google-cloud-vmwareengine/src/main/java/com/google/cloud/vmwareengine/v1/VmwareEngineClient.java