public ContainerStorageStats build() {
      if (containerId == null) {
        throw new IllegalStateException("No container is provided");
      }
      return new ContainerStorageStats(containerId, logicalStorageUsage, physicalStorageUsage, numberOfBlobs);
    }
Build a {@link ContainerStorageStats} based on the values in builder.
@return A new {@link ContainerStorageStats}.
ambry-api/src/main/java/com/github/ambry/server/storagestats/ContainerStorageStats.java