private CacheKey putOneThingInCache(DiskStorageCache cache) throws IOException {
    CacheKey key = new SimpleCacheKey("foo");
    byte[] value1 = new byte[101];
    value1[80] = 'c';
    cache.insert(key, WriterCallbacks.from(value1));
    return key;
  }
Verify that multiple threads can write to the cache at the same time.
imagepipeline-base/src/test/java/com/facebook/cache/disk/DiskStorageCacheTest.java