lanka","sudan","suriname","svalbard and jan mayen","swaziland","sweden","switzerland","syria","taiwan","tajikistan","tanzania","thailand","timor-leste","togo","tokelau","tonga","trinidad and tobago","tunisia","turkey","turkmenistan","turks and caicos islands","tuvalu","uganda","ukraine","united arab emirates","united kingdom","united states minor outlying islands","united states","uruguay","uzbekistan","vanuatu","venezuela","vatican city","vietnam","virgin islands (british)","virgin islands (us)","wallis and futuna","western...

      Headers
        .Builder()
        .add("foo: bar")
        .add(" foo: baz") // Name leading whitespace is trimmed.
        .add("foo : bak") // Name trailing whitespace is trimmed.
        .add("\tkey\t:\tvalue\t") // '\t' also counts as whitespace
        .add("ping:  pong  ") // Value whitespace is trimmed.
        .add("kit:kat") // Space after colon is not required.
        .build()