Sitecore and Azure Search- PostFailedForSomeDocumentsException error

When attempting to rebuild the master index of a Sitecore 9 instance in PAAS, the indexing would freeze and the following error was in the logs:

Exception: Sitecore.ContentSearch.Azure.Http.Exceptions.PostFailedForSomeDocumentsException
Message: Partial success for insert or update. Some documents succeeded, but at least one failed.

This traces back to the number of items being sent to Azure Search in a given patch. Inside the Sitecore.ContentSearch.Azure.DefaultIndexConfiguration.config configuration file is a node called cloudBatchBuilder with a child of maxDocuments. Decreasing this value from the default (1000 at the time of writing), should resolve this error.