give a different error on send vs recieve errors in amqp_simple_rpc calls
Adding amqp_set_timeout in c lib, adding net_rabbitmq_set_timeout in xs code.  This allows changing the timeout value on the socket used by this RabbitMQ connection
Recover merged but missing commit that makes client send a heartbeat back whenever it receives one.
The commit in question: https://github.com/omniti-labs/Net--RabbitMQ/pull/16