module: cache stat() results more aggressively
Reduce the number of stat() system calls that require() makes by caching the results more aggressively.
To avoid unbounded growth without implementing a LRU cache, scope the cache to the lifetime of the first call to require(). Recursive calls (i.e. require() calls in the included code) transparently profit from the cache.
The benchmarked application is the loopback-sample-app[0] and it sees the number of stat calls at start-up go down by 40%, from 4736 to 2810.