support for other message formats other than the default uint32(0)

[devigned]

amqp/client.go

Line 274 in ccafaa7

messageFormat = uint32(0) // Only message-format "0" is defined in spec.

One such example for non-default message formats is sending batch messages in Azure Service Bus. The following message format is used in the Java lib.

public static final int AMQP_BATCH_MESSAGE_FORMAT = 0x80013700; // 2147563264L;

via here

Perhaps, send should support TransferOption variadic arguments. Thoughts?

[vcabbage]

Would it make sense to add a Format field to the Message struct?

What is the format used for? The spec doesn't go into much detail about it.

[devigned]

I think it would make sense on the message.

I don’t know what else message format is used for. As you said, there not much to grok from the spec. I’ll ask amongst messaging folks and ping back if I get a better answer.

[vcabbage]

Looking at the usage in the Java lib, it seems the AMQP_BATCH_MESSAGE_FORMAT code might be a workaround for proton-j not supporting multiple data sections. This lib doesn't currently support that either, but only because I didn't need that when I first implemented it and I haven't decided on a good way to expose that on the message type. Would multiple data section support be useful to you?

https://github.com/Azure/azure-event-hubs-java/blob/c1365b956f2b0bf9f65db92385a6d433f5dba28c/azure-eventhubs/src/main/java/com/microsoft/azure/eventhubs/impl/MessageSender.java#L273-L305

[devigned]

That is precisely what I'm implementing right now, so yes, it would be useful. If you feel like multiple data section support is something you'd like to expose from this library, I'll gladly use it.