AssetImport time

I've got a relatively tiny Unity facebook-webgl project, with virtually no Asset Store assets, and every time I change one line of code, and flip to Unity, it takes 5 seconds to compile and re-import.

What can I do to speed this up, or find out what's taking the time?


Refresh: detecting if any assets need to be imported or removed ... Refresh: elapses 0.319887 seconds
Refreshing native plugins compatible for Editor in 0.70 ms, found 4 plugins.
Preloading 2 native plugins for Editor in 2.00 ms.

----- Total AssetImport time: 0.499791s, AssetImport time: 0.139940s, Asset hashing: 0.000000s [0 B, 0.000000 mb/s]

Refresh completed in 0.582982 seconds.
Refresh: detecting if any assets need to be imported or removed ...
Hashing assets (1 files)... 0.000 seconds
file read: 0.000 seconds (0.002 MB)
wait for write: 0.000 seconds (I/O thread blocked by consumer, aka CPU bound)
wait for read: 0.000 seconds (CPUT thread waiting for I/O thread, aka disk bound)
hash: 0.000 seconds
----- Compute hash(es) for 1 asset(s).

Refresh: elapses 0.336969 seconds
Updating Assets/Scripts/ButtonControllers/KeyButtonController.cs - GUID: 8a6ba88915768475b9644937467088db...
done. [Time: 144.168030 ms]
- Starting compile Library/ScriptAssemblies/Assembly-CSharp.dll
- Finished compile Library/ScriptAssemblies/Assembly-CSharp.dll
Symbols will be read from Temp/Assembly-CSharp.dll.mdb
Script Module: Assembly-CSharp.dll
Pass: 0 took 16 milliseconds
Pass: 1 took 16 milliseconds
- Starting compile Library/ScriptAssemblies/Assembly-CSharp-Editor.dll
- Finished compile Library/ScriptAssemblies/Assembly-CSharp-Editor.dll
Reloading assemblies after script compilation.
Begin MonoManager ReloadAssembly
Symbol file LoadedFromMemory is not a mono symbol file
Refreshing native plugins compatible for Editor in 0.68 ms, found 4 plugins.
Preloading 2 native plugins for Editor in 1.97 ms.
Mono: successfully reloaded assembly
- Completed reload, in 1.520 seconds
Initializing Unity.PackageManager (PackageManager) v2018.1.4 for Unity v2018.1.4f1
Registering platform support modules:
Registered platform support modules in: 0.0682028s.
Native extension for WebGL target not found
Native extension for OSXStandalone target not found
Native extension for Facebook target not found
Refreshing native plugins compatible for Editor in 0.90 ms, found 4 plugins.
Preloading 2 native plugins for Editor in 2.05 ms.

----- Total AssetImport time: 5.862182s, AssetImport time: 5.486597s, Asset hashing: 0.000347s [1.8 KB, 4.949615 mb/s]

Refresh completed in 5.947884 seconds.