more file api compliance
No MAP_NOCACHE on Linux
fresh rebar with fresh config: helps for building as dependency
Option lock (default) uses a rwlock to manage resource state (position, etc.) However, if the mmap resource is only to be used from one process, option 'nolock' can be used to avoid locking operations.
open option 'direct' makes it use so-called resource binaries which keep the memory mapped until the last reference is gone.