code: @Nullable
    public Date getDate(@Nonnull String field) {
      return ((Timestamp) get(field)).toDate();
    }
docs: Returns the value of the field as a Date.
  
  <p>This method ignores the global setting {@link
  FirestoreOptions#areTimestampsInSnapshotsEnabled}.
  
  @param field The path to the field.
  @throws RuntimeException if the value is not a Date.
  @return The value of the field.