code: @Nonnull
    public Query whereEqualTo(@Nonnull String field, @Nullable Object value) {
      return whereEqualTo(FieldPath.fromDotSeparatedString(field), value);
    }
docs: Creates and returns a new Query with the additional filter that documents must contain the
  specified field and the value should be equal to the specified value.
  
  @param field The name of the field to compare.
  @param value The value for comparison.
  @return The created Query.