public sealed class RowToken 

//ArcGIS Pro 2.5 extends the EditOperation.AddAttachment method to take a RowToken as a parameter.
//This allows you to create a feature, using EditOperation.CreateEx, and add an attachment in one transaction.

var editOpAttach = new EditOperation();
editOperation1.Name = string.Format("Create point in '{0}'", CurrentTemplate.Layer.Name);

var attachRowToken = editOpAttach.Create(this.CurrentTemplate, polygon);
editOpAttach.AddAttachment(attachRowToken, @"c:\temp\image.jpg");

//Must be within a QueuedTask
if (!editOpAttach.IsEmpty)
{
  var result = editOpAttach.Execute(); //Execute and ExecuteAsync will return true if the operation was successful and false if not
}

var create_rel1 = await QueuedTask.Run(() =>
{
  //This example uses a chained edit operation
  var edit_op = new EditOperation()
  {
    Name = "Create entities and a relationship",
    SelectNewFeatures = true
  };

  //We are just going to use the GDB objects in this one but
  //we could equally use feature layers/standalone tables

  //using Feature Class/Tables (works within Investigation or map)
  var org_fc = kg.OpenDataset<FeatureClass>("Organization");
  var person_tbl = kg.OpenDataset<Table>("Person");
  //Relationship table
  var emp_tbl = kg.OpenDataset<Table>("HasEmployee");

  var attribs = new Dictionary<string, object>();

  //New Organization
  attribs["Name"] = "Acme Ltd.";
  attribs["Description"] = "Specializes in household items";
  attribs["SHAPE"] = org_location;

  //Add it to the operation - we need the rowtoken
  var rowtoken = edit_op.Create(org_fc, attribs);

  attribs.Clear();//we are going to re-use the dictionary

  //New Person
  attribs["Name"] = "Bob";
  attribs["Age"] = "41";
  attribs["Skills"] = "Plumbing, Framing, Flooring";

  //Add it to the operation
  var rowtoken2 = edit_op.Create(person_tbl, attribs);

  attribs.Clear();

  //At this point we must execute the create of the entities
  if (edit_op.Execute())
  {
    //if we are here, the create of the entities was successful

    //Next, "chain" a second create for the relationship - this ensures that
    //Both creates (entities _and_ relation) will be -undone- together if needed
    //....in other words they will behave as if they are a -single- transaction
    var edit_op_rel = edit_op.CreateChainedOperation();

    //we need the names of the origin and destination relation properties
    var kg_prop_info = kg.GetPropertyNameInfo();
    //use the row tokens we held on to from the entity creates
    attribs[kg_prop_info.OriginIDPropertyName] = rowtoken.GlobalID;
    attribs[kg_prop_info.DestinationIDPropertyName] = rowtoken2.GlobalID;

    //Add any extra attribute information for the relation as needed
    attribs["StartDate"] = new DateTimeOffset(DateTime.Now);

    //Do the create of the relate
    edit_op_rel.Create(emp_tbl, attribs);
    return edit_op_rel.Execute();
  }
  return false;//Create of entities failed
});

var createRel = await QueuedTask.Run(() =>
{
  //This example uses a KnowledgeGraphRelationshipDescription
  var edit_op = new EditOperation()
  {
    Name = "Create entities and a relationship using a KG relate desc",
    SelectNewFeatures = true
  };

  //We are just going to use mapmembers in this example
  //we could equally use feature classes/tables
  var kg_layer = mv.Map.GetLayersAsFlattenedList()?
                .OfType<ArcGIS.Desktop.Mapping.KnowledgeGraphLayer>().First();
  //From the KG Layer get the relevant child feature layer(s) and/or standalone
  //table(s)
  var org_fl = kg_layer.GetLayersAsFlattenedList().OfType<FeatureLayer>()
                  .First(child_layer => child_layer.Name == "Organization");

  var person_stbl = kg_layer.GetStandaloneTablesAsFlattenedList()
                  .First(child_layer => child_layer.Name == "Person");

  var rel_stbl = kg_layer.GetStandaloneTablesAsFlattenedList()
                  .First(child_layer => child_layer.Name == "HasEmployee");

  var attribs = new Dictionary<string, object>();

  //New Organization
  attribs["Name"] = "Acme Ltd.";
  attribs["Description"] = "Specializes in household items";
  attribs["SHAPE"] = org_location;

  //Add it to the operation - we need the rowtoken
  var rowtoken_org = edit_op.Create(org_fl, attribs);

  attribs.Clear();//we are going to re-use the dictionary

  //New Person
  attribs["Name"] = "Bob";
  attribs["Age"] = "41";
  attribs["Skills"] = "Plumbing, Framing, Flooring";

  //Add it to the operation
  var rowtoken_person = edit_op.Create(person_stbl, attribs);

  attribs.Clear();

  //Create the new relationship using a KnowledgeGraphRelationshipDescription
  //Row handles act as the placeholders for the TO BE created new entities that will
  //be related
  var src_row_handle = new RowHandle(rowtoken_org);
  var dest_row_handle = new RowHandle(rowtoken_person);

  //Add any extra attribute information for the relation as needed
  attribs["StartDate"] = new DateTimeOffset(DateTime.Now);

  var rel_desc = new KnowledgeGraphRelationshipDescription(
                              src_row_handle, dest_row_handle, attribs);

  //Add the relate description to the edit operation
  edit_op.Create(rel_stbl, rel_desc);

  //Execute the create of the entities and relationship
  return edit_op.Execute();
});

internal static string GetDocumentTypeName(KnowledgeGraphDataModel kg_dm)
{
  var entity_types = kg_dm.GetEntityTypes();
  foreach (var entity_type in entity_types)
  {
    var role = entity_type.Value.GetRole();
    if (role == KnowledgeGraphNamedObjectTypeRole.Document)
      return entity_type.Value.GetName();
  }
  return "";
}

internal static string GetHasDocumentTypeName(KnowledgeGraphDataModel kg_dm)
{
  var rel_types = kg_dm.GetRelationshipTypes();
  foreach (var rel_type in rel_types)
  {
    var role = rel_type.Value.GetRole();
    if (role == KnowledgeGraphNamedObjectTypeRole.Document)
      return rel_type.Value.GetName();
  }
  return "";
}

internal async void AddDocumentRecord()
{

  await QueuedTask.Run(() =>
  {
    using (var kg = GetKnowledgeGraph())
    {
      var edit_op = new EditOperation()
      {
        Name = "Create Document Example",
        SelectNewFeatures = true
      };

      var doc_entity_name = GetDocumentTypeName(kg.GetDataModel());
      if (string.IsNullOrEmpty(doc_entity_name))
        return false;
      var hasdoc_rel_name = GetHasDocumentTypeName(kg.GetDataModel());
      if (string.IsNullOrEmpty(hasdoc_rel_name))
        return false;

      //Document can also be FeatureClass
      var doc_tbl = kg.OpenDataset<Table>(doc_entity_name);
      var doc_rel_tbl = kg.OpenDataset<Table>(hasdoc_rel_name);

      //This is the document to be added...file, image, resource, etc.
      var url = @"E:\Data\Temp\HelloWorld.txt";
      var text = System.IO.File.ReadAllText(url);

      //Set document properties
      var attribs = new Dictionary<string, object>();
      attribs["contentType"] = @"text/plain";
      attribs["name"] = System.IO.Path.GetFileName(url);
      attribs["url"] = url;
      //Add geometry if relevant
      //attribs["Shape"] = doc_location;

      //optional
      attribs["fileExtension"] = System.IO.Path.GetExtension(url);
      attribs["text"] = System.IO.File.ReadAllText(url);

      //optional and arbitrary - your choice
      attribs["title"] = System.IO.Path.GetFileNameWithoutExtension(url);
      attribs["keywords"] = @"text,file,example";
      attribs["metadata"] = "";

      //Specify any additional custom attributes added to the document
      //schema by the user as needed....
      //attribs["custom_attrib"] = "Foo";
      //attribs["custom_attrib2"] = "Bar";

      //Get the entity whose document this is...
      var org_fc = kg.OpenDataset<FeatureClass>("Organization");
      var qf = new QueryFilter()
      {
        WhereClause = "name = 'Acme'",
        SubFields = "*"
      };
      var origin_org_id = Guid.Empty;
      using (var rc = org_fc.Search(qf))
      {
        if (!rc.MoveNext())
          return false;
        origin_org_id = rc.Current.GetGlobalID();//For the relate
      }

      //Create the document row/feature
      var rowtoken = edit_op.Create(doc_tbl, attribs);
      if (edit_op.Execute())
      {
        //Create the relationship row
        attribs.Clear();
        //we need the names of the origin and destination relation properties
        var kg_prop_info = kg.GetPropertyNameInfo();
        //Specify the origin entity (i.e. the document 'owner') and
        //the document being related to (i.e. the document 'itself')
        attribs[kg_prop_info.OriginIDPropertyName] = origin_org_id;//entity
        attribs[kg_prop_info.DestinationIDPropertyName] = rowtoken.GlobalID;//document

        //Specify any custom attributes added to the has document
        //schema by the user as needed....
        //attribs["custom_attrib"] = "Foo";
        //attribs["custom_attrib2"] = "Bar";

        //"Chain" a second create for the relationship - this ensures that
        //Both creates (doc _and_ "has doc" relation) will be -undone- together if needed
        //....in other words they will behave as if they are a -single- transaction
        var edit_op_rel = edit_op.CreateChainedOperation();
        edit_op_rel.Create(doc_rel_tbl, attribs);
        return edit_op_rel.Execute();
      }
    }
    return false;
  });
}

// Create an EditOperation
EditOperation editOperation = new EditOperation();
editOperation.Name = "Create pole; create transformer bank; attach transformer bank to pole";

// Create the transformer bank
RowToken transformerBankToken = editOperation.Create(transformerBankLayer, transformerBankAttributes);

// Create a pole
RowToken poleToken = editOperation.Create(poleLayer, poleAttributes);

// Create a structural attachment association between the pole and the transformer bank
RowHandle poleHandle = new RowHandle(poleToken);
RowHandle transformerBankHandle = new RowHandle(transformerBankToken);

AssociationDescription poleAttachment = new AssociationDescription(AssociationType.Attachment, poleHandle, transformerBankHandle);

editOperation.Create(poleAttachment);

// Execute the EditOperation
editOperation.Execute();