Outbox storage operations pass through the body without copying

[danielmarbach]

As part of going through the code base I realized the driver natively support ReadOnlyMemory<T>. This means we no longer have to call ToArray(). Unfortunately the driver still does a ToArray under the covers but this might be resolved in future versions of the driver which would then make the new code more memory efficient.

The underlying representation remains the same. Example

Before

[{"MessageId": "8136fa26-5d31-43fe-9afb-b34100c5e778", "Options": [{"k": "Destination", "v": "ADuplicateMessageArrives.DownstreamEndpoint"}], "Body": new BinData(0, "eyJUZXJtaW5hdG9yIjpmYWxzZX0="), "Headers": [{"k": "NServiceBus.MessageId", "v": "8136fa26-5d31-43fe-9afb-b34100c5e778"}, {"k": "NServiceBus.MessageIntent", "v": "Send"}, {"k": "NServiceBus.RelatedTo", "v": "57670dea-7904-4a0f-b92e-2f66e40f72aa"}, {"k": "NServiceBus.ConversationId", "v": "bda75aaa-eaf6-4640-971f-b34100c5e75f"}, {"k": "NServiceBus.CorrelationId", "v": "57670dea-7904-4a0f-b92e-2f66e40f72aa"}, {"k": "NServiceBus.ReplyToAddress", "v": "ADuplicateMessageArrives.OutboxEndpoint"}, {"k": "NServiceBus.OriginatingMachine", "v": "danielsacstudio"}, {"k": "NServiceBus.OriginatingEndpoint", "v": "ADuplicateMessageArrives.OutboxEndpoint"}, {"k": "$.diagnostics.originating.hostid", "v": "b65da644d5b5b3ee8cd445df3f7d13e9"}, {"k": "NServiceBus.ContentType", "v": "application/json"}, {"k": "NServiceBus.EnclosedMessageTypes", "v": "NServiceBus.AcceptanceTests.Outbox.When_a_duplicate_message_arrives+SendOrderAcknowledgement, NServiceBus.Storage.MongoDB.AcceptanceTests, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"}, {"k": "NServiceBus.Version", "v": "10.0.0"}, {"k": "NServiceBus.TimeSent", "v": "2025-08-22 12:00:32:824299 Z"}]}]

"Body": new BinData(0, "eyJUZXJtaW5hdG9yIjpmYWxzZX0=")

represents {"Terminator":false}

After

[{"MessageId": "903e7729-eecf-4730-ab7a-b34100c516e9", "Options": [{"k": "Destination", "v": "ADuplicateMessageArrives.DownstreamEndpoint"}], "Body": new BinData(0, "eyJUZXJtaW5hdG9yIjp0cnVlfQ=="), "Headers": [{"k": "NServiceBus.MessageId", "v": "903e7729-eecf-4730-ab7a-b34100c516e9"}, {"k": "NServiceBus.MessageIntent", "v": "Send"}, {"k": "NServiceBus.RelatedTo", "v": "cf692566-98cd-4ce6-b2ef-b34100c516d6"}, {"k": "NServiceBus.ConversationId", "v": "6d9be290-f079-475d-8651-b34100c516d6"}, {"k": "NServiceBus.CorrelationId", "v": "cf692566-98cd-4ce6-b2ef-b34100c516d6"}, {"k": "NServiceBus.ReplyToAddress", "v": "ADuplicateMessageArrives.OutboxEndpoint"}, {"k": "NServiceBus.OriginatingMachine", "v": "danielsacstudio"}, {"k": "NServiceBus.OriginatingEndpoint", "v": "ADuplicateMessageArrives.OutboxEndpoint"}, {"k": "$.diagnostics.originating.hostid", "v": "b65da644d5b5b3ee8cd445df3f7d13e9"}, {"k": "NServiceBus.ContentType", "v": "application/json"}, {"k": "NServiceBus.EnclosedMessageTypes", "v": "NServiceBus.AcceptanceTests.Outbox.When_a_duplicate_message_arrives+SendOrderAcknowledgement, NServiceBus.Storage.MongoDB.AcceptanceTests, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"}, {"k": "NServiceBus.Version", "v": "10.0.0"}, {"k": "NServiceBus.TimeSent", "v": "2025-08-22 11:57:34:854985 Z"}]}]

new BinData(0, "eyJUZXJtaW5hdG9yIjp0cnVlfQ==")

represents {"Terminator":true}