<!-- NEW4 — TEST 4 · THE QUILT · part 278 -->
p.knownActions,

			lastKnownAction =
				knownActionsForClip[ knownActionsForClip.length - 1 ],

			byClipCacheIndex = action._byClipCacheIndex;

		lastKnownAction._byClipCacheIndex = byClipCacheIndex;
		knownActionsForClip[ byClipCacheIndex ] = lastKnownAction;
		knownActionsForClip.pop();

		action._byClipCacheIndex = null;


		const actionByRoot = actionsForClip.actionByRoot,
			rootUuid = ( action._localRoot || this._root ).uuid;

		delete actionByRoot[ rootUuid ];

		if ( knownActionsForClip.length === 0 ) {

			delete actionsByClip[ clipUuid ];

		}

		this._removeInactiveBindingsForAction( action );

	}

	_removeInactiveBindingsForAction( action ) {

		const bindings = action._propertyBindings;

		for ( let i = 0, n = bindings.length; i !== n; ++ i ) {

			const binding = bindings[ i ];

			if ( -- binding.referenceCount === 0 ) {

				this._removeInactiveBinding( binding );

			}

		}

	}

	_lendAction( action ) {

		// [ active actions |  inactive actions  ]
		// [  active actions >| inactive actions ]
		//                 s        a
		//                  <-swap->
		//                 a        s

		const actions = this._actions,
			prevIndex = action._cacheIndex,

			lastActiveIndex = this._nActiveActions ++,

			firstInactiveAction = actions[ lastActiveIndex ];

		action._cacheIndex = lastActiveIndex;
		actions[ lastActiveIndex ] = action;

		firstInactiveAction._cacheIndex = prevIndex;
		actions[ prevIndex ] = firstInactiveAction;

	}

	_takeBackAction( action ) {

		// [  active actions  | inactive actions ]
		// [ active actions |< inactive actions  ]
		//        a        s
		//         <-swap->
		//        s        a

		const actions = this._actions,
			prevIndex = action._cacheIndex,

			firstInactiveIndex = -- this._nActiveActions,

			lastActiveAction = actions[ firstInactiveIndex ];

		action._cacheIndex = firstInactiveIndex;
		actions[ firstInactiveIndex ] = action;

		lastActiveAction._cacheIndex = prevIndex;
		actions[ prevIndex ] = lastActiveAction;

	}

	// Memory management for PropertyMixer objects

	_addInactiveBinding( binding, rootUuid, trackName ) {

		const bindingsByRoot = this._bindingsByRootAndName,
			bindings = this._bindings;

		let bindingByName = bindingsByRoot[ rootUuid ];

		if ( bindingByName === undefined ) {

			bindingByName = {};
			bindingsByRoot[ rootUuid ] = bindingByName;

		}

		bindingByName[ trackName ] = binding;

		binding._cacheIndex = bindings.length;
		bindings.push( binding );

	}

	_removeInactiveBinding( binding ) {

		const bindings = this._bindings,
			propBinding = binding.binding,
			rootUuid = propBinding.rootNode.uuid,
			trackName = propBinding.path,
			bindingsByRoot = this._bindingsByRootAndName,
			bindingByName = bindingsByRoot[ rootUuid ],

			lastInactiveBinding = bindings[ bindings.length - 1 ],
			cacheIndex = binding._cacheIndex;

		lastInactiveBinding._cacheIndex = cacheIndex;
		bindings[ cacheIndex ] = lastInactiveBinding;
		bindings.pop();

		delete bindingByName[ trackName ];

		if ( Object.keys( bindingByName ).length === 0 ) {

			delete bindingsByRoot[ rootUuid ];

		}

	}

	_lendBinding( binding ) {

		const bindings = this._bindings,
			prevIndex = binding._cacheIndex,

			lastActiveIndex = this._nActiveBindings ++,

			firstInactiveBinding = bindings[ lastActiveIndex ];

		binding._cacheIndex = lastActiveIndex;
		bindings[ lastActiveIndex ] = binding;

		firstInactiveBinding._cacheIndex = prevIndex;
		bindings[ prevIndex ] = firstInactiveBinding;

	}

	_takeBackBinding( binding ) {

		const bindings = this._bindings,
			prevIndex = binding._cacheIndex,

			firstInactiveIndex = -- this._nActiveBindings,

			lastActiveBinding = bindings[ firstInactiveIndex ];

		binding._cacheIndex = firstInactiveIndex;
		bindings[ firstInactiveIndex ] = binding;

		lastActiveBinding._cacheIndex = prevIndex;
		bindings[ prevIndex ] = lastActiveBinding;

	}


	// Memory management of Interpolants for weight and time scale

	_lendControlInterpolant() {

		const interpolants = this._controlInterpolants,
			lastActiveIndex = this._nActiveControlInterpolants ++;

		let interpolant = interpolants[ lastActiveIndex ];

		if ( interpolant === undefined ) {

			interpolant = new LinearInterpolant(
				new Float32Array( 2 ), new Float32Array( 2 ),
				1, _controlInterpolantsResultBuffer );

			interpolant.__cacheIndex = lastActiveIndex;
			interpolants[ lastActiveIndex ] = interpolant;

		}

		return interpolant;

	}

	_takeBackControlInterpolant( interpolant ) {

		const interpolants = this._controlInterpolants,
			prevIndex = interpolant.__cacheIndex,

			firstInactiveIndex = -- this._nActiveControlInterpolants,

			lastActiveInterpolant = interpolants[ firstInactiveIndex ];

		interpolant.__cacheIndex = firstInactiveIndex;
		interpolants[ firstInactiveIndex ] = interpolant;

		lastActiveInterpolant.__cacheIndex = prevIndex;
		interpolants[ prevIndex ] = lastActiveInterpolant;

	}

	/**
	 * Returns an