The length in bytes of the source file.
The optimal initial bucket count a StringCache should have.
assert(optimalBucketCount(1) == 2); assert(optimalBucketCount(9000 * 32) == 16384); static if (size_t.sizeof == ulong.sizeof) assert(optimalBucketCount(100_000_000_000UL) == 1 << 30);
Helper function used to avoid too much allocations while lexing.