.NET for Android warning XA5302
The XA5302 warning is generated if we detect MSBuild building the project multiple times in parallel.
You should not encounter this under normal circumstances in IDEs or at the command-line.
You could also encounter this warning if MSBuild crashes, suffer power loss, etc. You can safely delete the file mentioned in the warning message as a last resort.
Consider submitting a bug if you are getting this failure under normal circumstances.