Too much usage "SerializedFile" on Memory profiler

Hello. In my project, when loaded scene, about 400mb, under 150 assetbundles are caching and synchronized on to disk using WWW.assetbundle which WWW not Disposed into the C# Dictionary. Then checking the memory usage and compare with built single scene not used assetbundle version, assetbundle scene version usage twice more memory size.
So four things of my questions.
first. what are the MemoryProfiler's "SerializedFile", "ManagedHeap.ReservedUnusedSize", "ManagedHeal.UsedSize" ?...

Too much usage "SerializedFile" on Memory profiler