sqlbrite/src/main/java/com/squareup/sqlbrite3/QueryObservable.java
@CheckResult @NonNull
  public final <T> Observable<List<T>> mapToList(@NonNull Function<Cursor, T> mapper) {
    return lift(Query.mapToList(mapper));
  }
@CheckResult @NonNull
  public final <T> Observable<List<T>> mapToList(@NonNull Function<Cursor, T> mapper) {
    return lift(Query.mapToList(mapper));
  }
Given a function mapping the current row of a {@link Cursor} to {@code T}, transform each
emitted {@link Query} to a {@code List<T>}.
<p>
Be careful using this operator as it will always consume the entire cursor and create objects
for each row, every time this observable emits a new query. On tables whose queries update
frequently or very large result sets this can result in the creation of many objects.
<p>
This method is equivalent to:
<pre>{@code
flatMap(q -> q.asRows(mapper).toList())
}</pre>
and a convenience operator for:
<pre>{@code
lift(Query.mapToList(mapper))
}</pre>
<p>
Consider using {@link Query#asRows} if you need to limit or filter in memory.

@param mapper Maps the current {@link Cursor} row to {@code T}. May not return null.