UnityWebRequest leaks memory on Web Player when files are downloaded and then freed

6.6.X

As Designed

Thank you for reporting a bug to Unity. After reviewing the behavior, we've confirmed that it is a known limitation of the WebGL GC implementation and not a bug with UnityWebRequest. We encourage you to see - https://issuetracker.unity3d.com/issues/garbage-collector-memory-leak-when-allocating-and-deallocating-memory-in-web-builds for more details. We suggest couple of work around - 1. Use the exposed nativeData to access the downloaded bytes directly bypassing allocation that needs to be cleaned up by the GC. 2. Use a smaller chunk to read in the data. This will drastically reduce the probability of GC falsely pinning the memory as in use. E,g - a 100mb allocation in 250mb wasm has a 40% chance of being not cleaned up by GC, where a 64kb allocation in 250mb wasm has a 0.025% chance of not cleaned up by GC. 3. Preallocated the big buffer knowing it may be not released, and re-use it for the duration of the application lifetime. We will close this case as 'As Designed.' If you have feedback on how the feature could better meet your needs, please let us know - we value your input and consider it in future improvements.