chore: remove unused castToBSON method

Author: jimlambie

lib/index.js

@@ -543,21 +543,6 @@ function getSchemaOrParent (key, schema) {
   }
 }
 
-/**
- * Takes object and casts fields to BSON types as per this model's schema
- *
- * @param {object} obj
- * @return undefined
- * @api private
- */
-// DataStore.prototype.castToBSON = function (obj) {
-//   // TODO: Do we need to handle casting for all fields, or will `_id` be the only BSON specific type?
-//   //      this is starting to enter ODM land...
-//   if (typeof obj._id === 'string' && ObjectID.isValid(obj._id) && obj._id.match(/^[a-fA-F0-9]{24}$/)) {
-//     obj._id = ObjectID.createFromHexString(obj._id)
-//   }
-// }
-
 /**
  *
  */