class NoSeekMemoryIO(object): """Shim around MemoryIO which blocks access to everything but read. Used to ensure seek API isn't being depended on.""" def __init__(self, *args): self.underlying = MemoryIO(*args) def read(self, n): return self.underlying.read(n) def tell(self): return self.underlying.tell() def seek(self, *args): raise AssertionError("fastavro reader should not depend on seek")