void enableWrite(Connection conn) {
        if (Thread.currentThread() == thread) {
            handleEnableWrite(conn);
        } else {
            postCommand(new EnableWriteCmd(conn));
        }
    }
Requests an asynchronous enabling of write events for a
connection.

@param conn the connection to enable write events for
jrt/src/com/yahoo/jrt/TransportThread.java