// Stat cache.
constexpr char kStatCacheMaxEntries[] = "GCS_STAT_CACHE_MAX_ENTRIES";
constexpr size_t kStatCacheDefaultMaxEntries = 1024;

// How to upload new data when Flush() is called multiple times.
// By default the entire file is reuploaded.
constexpr char kAppendMode[] = "GCS_APPEND_MODE";
// If GCS_APPEND_MODE=compose then instead the new data is uploaded to a