public static <T> Values<T> of(Iterable<T> elems) {
    return new Values<>(elems, Optional.absent(), Optional.absent(), false);
  }
@Test
  public void testCreateExplicitSchema() {
    PCollection<String> out =
        p.apply(
            Create.of("a", "b", "c", "d")
                .withSchema(
                    STRING_SCHEMA,
                    TypeDescriptors.strings(),
                    s -> Row.withSchema(STRING_SCHEMA).addValue(s).build(),
                    r -> r.getString("field")));
    assertThat(out.getCoder(), instanceOf(SchemaCoder.class));
  }