code: public final AtomicOutputStream createBlob(String key, SettableBlobMeta meta) throws KeyAlreadyExistsException {
          return createBlobToExtend(key, meta);
      }
docs: Client facing API to create a blob.
  @param key blob key name.
  @param meta contains ACL information.
  @return AtomicOutputStream returns an output stream into which data can be written.
  @throws AuthorizationException
  @throws KeyAlreadyExistsException