class Google::Cloud::Env::FileSystem

def initialize
  @overrides = nil
  @cache = LazyDict.new do |path, binary|
    if binary
      File.binread path
    else
      File.read path
    end
  rescue IOError, SystemCallError
    nil
  end
  # This mutex protects the overrides variable. Its setting (i.e.
  # whether nil or an overrides hash) will not change within a
  # synchronize block.
  @mutex = Thread::Mutex.new
end