tinymachine/src/main/java/de/halfbit/tinymachine/TinyMachine.java
public TinyMachine setTraceTag(String tag) {
        mTraceTag = tag;
        if (mTraceTag != null) {
            log("current state", null);
        }
        return this;
    }
public TinyMachine setTraceTag(String tag) {
        mTraceTag = tag;
        if (mTraceTag != null) {
            log("current state", null);
        }
        return this;
    }
Enables traces and sets tag to be used for <code>Log.d()</code> output.
<code>TinyMachine</code> will trace all processed events and state transitions including
events for which handlers in current state are missed.

@param tag   the name of tag to be used in <code>Log.d()</code>
@return      this instance