memfs: a simple in-memory filesystem

This library implements a simple in-memory filesystem for Fuchsia.

It currently has no settings. Because it uses the C allocator, it can expand to fill all available memory and the max size values from POSIX statvfs() and FIDL fuchsia.io.Node.QueryFilesystem() may not have much meaning.

Usage

Typical in-tree C++ users should depend on //src/storage/memfs:cpp and #include "src/storage/memfs/scoped_memfs.h".

// Use a separate message loop to avoid deadlock on shutdown. The loop should
// enclose the memfs lifetime.
async::Loop loop(kAsyncLoopConfigNoAttachToCurrentThread);
loop.StartThread();

zx::result<ScopedMemfs> memfs =
    ScopedMemfs::CreateMountedAt(loop.dispatcher(), "/my_tmp");

Out-of-tree and C users should depend on //src/storage/memfs and #include <lib/memfs/memfs.h>.