builder = builder.type(MediaType.valueOf(header.type()));
if (header.title().length() != 0)
builder = builder.parameter("title", header.title());
if (header.anchor().length() != 0)
builder = builder.parameter("anchor", header.anchor());
if (header.media().length() != 0)
builder = builder.parameter("media", header.media());
if (header.hreflang().length() != 0)
builder = builder.parameter("hreflang", header.hreflang());
for (Link.Extension ext: header.extensions()) {
builder = builder.parameter(ext.name(), ext.value());