Allow the user to limit the number of threads OneDrive spawns in large data migration operations
When a user is connecting a new computer or changing the settings of an older computer - such that the new setting will store all files locally - and - in the cloud - OneDrive spawns way too many threads resulting in I/O blocking. Instead, either limit the copy operation to no more than n/2 threads where n is the number of cores in the computer - or - allow the user to manually set the maximum number of threads.
The reason for this is I was copying everything to @local (roughly 240GB) and it took on a 1Gbit network with a 1Gbit uplink roughly 24 hours with observable speeds between 1KB/s up to 2MB/s and I/O at 100%. My guesstimate is that the number of threads are thrashing the hard drive writing small blocks. Fewer threads would lead to less thrashing - and might lead to improved network performance as well.