Use Unsafe Dokan Operations?

[dedmen]

This is a sub-interface of IDokanOperations that can optionally be implemented to get access to the raw, unmanaged buffers for ReadFile() and WriteFile() for performance optimization. Marshalling the unmanaged buffers to and from byte[] arrays for every call of these APIs incurs an extra copy that can be avoided by reading from or writing directly to the unmanaged buffers.

https://dokan-dev.github.io/dokan-dotnet-doc/html/interface_dokan_net_1_1_i_dokan_operations_unsafe.html

Sounds like this is atleast worth a try. Though our file copy speed is already "good enough"