def on_tag_lost(obj=nil, &block)
	  @on_tag_lost_obj = obj
      @on_tag_lost = Proc.new { |device, obj_ptr, tag, proto|
	    yield self, tag.read_string, object_for(obj_ptr)
	}
      Klass.set_OnTagLost2_Handler(@handle, @on_tag_lost, pointer_for(obj))
    end
def on_tag_lost(obj=nil, &block)
	  @on_tag_lost_obj = obj
      @on_tag_lost = Proc.new { |device, obj_ptr, tag, proto|
	    yield self, tag.read_string, object_for(obj_ptr)
	}
      Klass.set_OnTagLost2_Handler(@handle, @on_tag_lost, pointer_for(obj))
    end
Sets a tag lost handler callback function. This is called when a tag is removed from the reader

 @param [String] obj Object to pass to the callback function. This is optional.
 @param [Proc] Block When the callback is executed, the device and object are yielded to this block.
 @example
     rfid.on_tag_lost do |device, tag, obj|
       puts "Tag #{tag} removed"
     end
 As this runs in it's own thread, be sure that all errors are properly handled or the thread will halt and not fire any more.
 @return [Boolean] returns true or raises an error