code: public static HttpHeader header(String name, String value) {
  		return new HttpHeader(name, singletonList(value));
  	}
docs: Create a header with a single value.
  
  @param name Header name, must not be blank.
  @param value Header value.
  @return Header.
  @throws NullPointerException If {@code name} or {@code value} are {@code null}.
  @throws IllegalArgumentException If {@code name} is blank.