### Question:
HttpHeaders implements Iterable<HttpHeader> { @Override public String toString() { return Iterables.toString(nettyHeaders); } private  HttpHeaders(Builder builder); Set<String> names(); Optional<String> get(CharSequence name); List<String> getAll(CharSequence name); boolean contains(CharSequence name); @Override Iterator<HttpHeader> iterator(); void forEach(BiConsumer<String, String> consumer); Builder newBuilder(); @Override String toString(); @Override int hashCode(); @Override boolean equals(Object obj);  }### Answer:
@Test public void convertsHeadersToString() { assertThat(headers.toString(), is("[header1=val1, header2=val2a, header2=val2b]")); }