1.1.0

• Changed error message when attempting to await a non-awaitable object (i.e., it has no __await__).
• Fixed coroutine iterator reference leak.
• Fixed reference leak in error callbacks.
• Fixed early exit of pyawaitable_unpack_arb if a NULL value was saved.
• Added integer value saving and unpacking (pyawaitable_save_int and pyawaitable_unpack_int).
• Callbacks are now preallocated for better performance.
• Fixed reference leak in the coroutine send() method.