code: public final TcpClient resolver(AddressResolverGroup<?> resolver) {
  		Objects.requireNonNull(resolver, "resolver");
  		return bootstrap(b -> b.resolver(resolver));
  	}
docs: Assign an {@link AddressResolverGroup}.
  
  @param resolver the new {@link AddressResolverGroup}
  
  @return a new {@link TcpClient}