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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def send_async(self, transaction, headers=None):
 """Submit a transaction to the Federation with the mode `async`. Args: transaction (dict):
 the transaction to be sent to the Federation node(s). headers (dict):
 Optional headers to pass to the request. Returns: dict: The transaction sent to the Federation node(s). """

        return self.transport.forward_request(
            method='POST',
            path=self.path,
            json=transaction,
            params={'mode': 'async'},
            headers=headers)