code: static public Set<String> parseProtocolRequestHeader(String value) {
          Set<String> subprotocols = new LinkedHashSet<>();
          
          if (!StringUtils.isEmpty(value)) {
              String[] values = value.split(",");
              for (String v : values) {
                  subprotocols.add(v.trim());
              }
          }
          
          return subprotocols;
      }
docs: Parses header `Sec-WebSocket-Protocol: chat, superchat` into a list
  such as `chat`, and `superchat`.
  @param value The header value
  @return A set of values or null if value was null or empty