MsgContext mCtx=createMsgContext();
Msg msg=(Msg)mCtx.getMsg(0);
msg.reset();
C2BConverter c2b=mCtx.getConverter();
msg.appendByte( SHM_WRITE_SLOT );
appendString( msg, slotName, c2b );
// number of channels for this instance
msg.appendInt( 0 );
msg.appendInt( 0 );