Bug 168806 [DataBinding] Realm.ensureWorkerThreadIsRunning() doesn't start a new thread
bundles/org.eclipse.core.databinding.observable/src/org/eclipse/core/databinding/observable/Realm.java
private static ThreadLocal defaultRealm = new ThreadLocal();
	/**
	 * Returns the default realm for the calling thread, or <code>null</code>
	 * if no default realm has been set.
	 * 
	 * @return the default realm, or <code>null</code>
	 */
	public static Realm getDefault() {
		return (Realm) defaultRealm.get();
	}
	/**
	 * Sets the default realm for the calling thread. Each thread can have its
	 * own default realm.
	 * 
	 * @param realm
	 *            the realm, or <code>null</code> to clear the current default
	 *            realm
	 */
	public static void setDefault(Realm realm) {
		defaultRealm.set(realm);
	}