code: public <T> RspList<T> castMessage(Collection<Address> dests, byte[] data, int offset, int length,
                                        RequestOptions opts) throws Exception {
          return castMessage(dests, new Buffer(data, offset, length), opts);
      }
docs: Sends a message to all members and expects responses from members in dests (if non-null).
  @param dests A list of group members from which to expect responses (if the call is blocking).
  @param data The buffer
  @param offset the offset into data
  @param length the number of bytes to send
  @param opts A set of options that govern the call. See {@link org.jgroups.blocks.RequestOptions} for details
  @return RspList A list of Rsp elements, or null if the RPC is asynchronous
  @throws Exception If the request cannot be sent
  @since 4.0