The com.google.cloud.datastore package mentioned in most of Google's Java documentation for Datastore provides a Builder class with a setNull method used to set any property value to null, e.g.
FullEntity.Builder<IncompleteKey> builder = FullEntity.newBuilder();
builder.setNull("propertyName");
Google Cloud Dataflow/Apache Beam's DatastoreIO class requires Entities in the package com.google.datastore.v1, and the builder methods do not include a similar setNull method. How do I set a property to null using the V1 Java APIs?