@type t() :: %PolarExpress.Schemas.EventCreateExternalCustomer{
  external_customer_id: String.t() | nil,
  external_id: String.t() | nil,
  external_member_id: String.t() | nil,
  metadata: PolarExpress.Schemas.EventMetadataInput.t() | nil,
  name: String.t() | nil,
  organization_id: String.t() | nil,
  parent_id: String.t() | nil,
  timestamp: DateTime.t() | nil
}

• external_customer_id - ID of the customer in your system associated with the event.
• external_id - Your unique identifier for this event. Useful for deduplication and parent-child relationships. Nullable.
• external_member_id - ID of the member in your system within the customer's organization who performed the action. Used for member-level attribution in B2B. Nullable.
• metadata - Key-value object allowing you to store additional information about the event. Some keys like _llm are structured data that are handled specially by Polar.

The key must be a string with a maximum length of 40 characters. The value must be either:

• A string with a maximum length of 500 characters
• An integer
• A floating-point number
• A boolean

You can store up to 50 key-value pairs.

• name - The name of the event.
• organization_id - The ID of the organization owning the event. Required unless you use an organization token. Nullable.
• parent_id - The ID of the parent event. Can be either a Polar event ID (UUID) or an external event ID. Nullable.
• timestamp - The timestamp of the event. Format: date-time.