feat(api): add average cost to positions (#78)

.stats.yml

@@ -1,2 +1,2 @@
 configured_endpoints: 31
-openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/clear-street%2Fstudio-sdk-507601d533175bf3b74a3b04c29d55029c585b24a4ec873bc43d93fe76528076.yml
+openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/clear-street%2Fstudio-sdk-f04f51a2adbacf75b26ed0b3cd1920c8e2dc63a35c78a579bb8f007247307082.yml

src/resources/shared.ts

@@ -267,19 +267,24 @@ export interface Position {
   /**
    * Account ID for the account.
    */
-  account_id?: string;
+  account_id: string;
 
   /**
    * Account number for the account.
    */
-  account_number?: string;
+  account_number: string;
+
+  /**
+   * The average cost of the position.
+   */
+  average_cost: number;
 
   /**
    * String representation of quantity.
    */
-  quantity?: string;
+  quantity: string;
 
-  symbol?: string;
+  symbol: string;
 }
 
 export interface RegtMarginSimulation {