added extra doc to socket options

README.md

@@ -6,7 +6,7 @@ in production. Bug reports welcome.
 To Install
 ==========
 
-First, get [ØMQ 2.1], >2.1.3 is required. [Homebrew] on Mac will get you what
+First, get [ØMQ 2.1], >2.1.0 is required. [Homebrew] on Mac will get you what
 you need.
 
 Then use [npm] to install zeromq.node:
@@ -65,6 +65,41 @@ oh such fun.
 
  * close() - Closes the socket
 
+#### Socket Options
+
+   To set a socket option on a socket, use socket[property].  For example,
+
+   socket['identity'] = "mainLoop";
+
+   The following properties are available (the ZMQ_XXX constant describes the name in the ZeroMQ documentation available at [ØMQ setsockopt API]):
+
+   * ioThreadAffinity - set affinity for IO thread (integer, ZMQ_AFFINITY);
+   * backlog - set connection backlog for listening sockets (integer, ZMQ_BACKLOG);
+   * identity - set the socket identity (name) (string, ZMQ_IDENTITY);
+   * lingerPeriod - set the linger period in milliseconds (integer, -1 = unlimited, ZMQ_LINGER);
+   * receiveBufferSize - set the kernel receive buffer size (integer, 0 = OS default, ZMQ_RCVBUF);
+   * sendBufferSize - set the kernel receive buffer size (integer, 0 = OS default, ZMQ_RCVBUF);
+
+   The following apply to message buffering and reconnection:
+
+   * reconnectionInterval - set the time to wait between reconnection attempts in milliseconds (ZeroMQ attempts to reconnect broken connection automatically behind the scenes) (integer, ZMQ_RECONNECT_IVL)
+   * highWaterMark - set high water mark (in number of outstanding messages) before buffered messages start being dropped or swapped to disk (integer, zero = unlimited, ZMQ_HWM);
+   * diskOffloadSize - set the amount of disk swap space in bytes for buffering messages in case of disconnection (integer, ZMQ_SWAP)
+
+   The following options are applicable to multicast:
+   * multicastLoop - set whether multicast can go over loopback or not (boolean, ZMQ_MCAST_LOOP);
+   * multicastDataRate - set maximum multicast transmission rate in kbits per second (integer, ZMQ_RATE);
+   * multicastRecovery - set maximum multicast recovery interval in seconds (integer, ZMQ_RECOVERY_IVL)
+
+   The following properties are exposed but not normally used by client code (they are used internally by the library):
+
+   * _fd - File descriptor (integer, ZMQ_FD);
+   * _ioevents - Event loop used internally (ZMQ_EVENTS);
+   * _receiveMore - Message has more parts (boolean, ZMQ_RCVMORE);
+   * _subscribe - Subscribe to a channel (see subscribe() method) (string, ZMQ_SUBSCRIBE);
+   * _unsubscribe - Unsubscribe to a channel (see unsubscribe() method) (string, ZMQ_UNSUBSCRIBE);
+
+
 #### Events
 
  * message - A message was received. The arguments are the parts of the
@@ -102,6 +137,7 @@ Licensed under the very permissive [MIT License].
 [ØMQ 2.1]: http://www.zeromq.org/intro:get-the-software
 [Homebrew]: http://mxcl.github.com/homebrew/
 [ØMQ API]: http://api.zeromq.org/
+[ØMQ setsockopt API]: http://api.zeromq.org/2-1-3:zmq-setsockopt
 [zmq_socket]: http://api.zeromq.org/zmq_socket.html
 [zmq_connect]: http://api.zeromq.org/zmq_connect.html
 [zmq_bind]: http://api.zeromq.org/zmq_bind.html