message: Fix mutex condition
diff: @@ -161,6 +161,7 @@ void Cleanup(TF_RandomAccessFile* file) {
  }
  static void FillBuffer(uint64_t start, GCSFile* gcs_file, TF_Status* status) {
  + ABSL_EXCLUSIVE_LOCKS_REQUIRED(gcs_file->buffer_mutex)
  gcs_file->buffer_start = start;
  gcs_file->buffer.resize(gcs_file->buffer_size);
  auto read =
  @@ -463,11 +464,14 @@ void NewRandomAccessFile(const TF_Filesystem* filesystem, const char* path,
  const std::string& path, uint64_t offset, size_t n,
  char* buffer, TF_Status* status) -> int64_t {
  // TODO(vnvo2409): Check for `stat_cache`.
  - auto read =
  - is_cache_enabled
  - ? gcs_file->file_block_cache->Read(path, offset, n, buffer, status)
  - : LoadBufferFromGCS(path, offset, n, buffer, &gcs_file->gcs_client,
  + int64_t read = 0;
  + if (is_cache_enabled) {
  + absl::ReaderMutexLock l(&gcs_file->block_cache_lock);
  + read = gcs_file->file_block_cache->Read(path, offset, n, buffer, status);
  + } else {
  + read = LoadBufferFromGCS(path, offset, n, buffer, &gcs_file->gcs_client,
  status);
  + }
  if (TF_GetCode(status) != TF_OK) return -1;
  if (read < n)
  TF_SetStatus(status, TF_OUT_OF_RANGE, "Read less bytes than requested");
  