Createrelateditem

Creates a related item (comments, tasks, and contacts) and associates it with a case. A Related Item is a resource that is associated with a case. It may or may not have an external identifier linking it to an external resource (for example, a contactArn). All Related Items have their own internal identifier, the relatedItemArn. Examples of related items include comments and contacts. If you provide a value for performedBy.userArn you must also have DescribeUser permission on the ARN of ...