Bulk update user data

Bulk updates user data. This endpoint adds and overwrites user profile fields as needed. It does not modify top-level fields omitted from the request body. <br/><br/>If you'd like to merge (rather than overwrite) a user profile's top-level objects with the values provided for them in the request body, set <code>mergeNestedObjects</code> to <code>true</code>.<br/><br/>When updating an existing field, you cannot change its data type (the new value must have the same data type as the old value).<br/><br/>When adding a new field, remember that each project has a soft limit of 1,000 unique user profile fields (across all its users, with a field's uniqueness determined by its name and position on the user profile). <br/><br/>Iterable handles requests to this endpoint separately from requests to single-user endpoints (<code>update</code>, <code>updateEmail</code>, <code>updateSubscriptions</code>, etc.). For a given user, in a short period of time, only use single-user calls or bulk update calls. Otherwise, results may be inconsistent.<br/><br/>When updating the <code>emailListIds</code> field, this endpoint does not generate subscribe or unsubscribe events. The same is true for updates to <code>unsubscribedChannelIds</code> and <code>unsubscribedMessageTypeIds</code> (but these can only be updated by this endpoint in projects where the opt-in message types feature is not enabled).<br/><br/>Learn about <a href="https://support.iterable.com/hc/articles/29156459027348">identifying users by <code>userId</code> and <code>email</code></a>.<br/><br/><b>Max size of request body</b>: 4MB<br/><b>Rate limit</b>: 5 requests/second, per project