Hey @ofgirichardsonb . Unfortunately that’s one of the message headers you can’t set with REST. It’s too bad we don’t have parity across all our APIs and protocols. Couple options:
Use another header (HTTP Content Type or Content Encoding) IMessage.HttpContentType Property Maybe a User Property instead? I don’t know much about WASM or Blazor or anything, but maybe there’s other messaging libraries you could try, might give you better performance than REST?
MQTT: GitHub - dotnet/MQTTnet: MQTTnet is a high performance .NET library for MQTT based communication. It provides a MQTT client and a MQTT server (broker). The implementation is based on the documentation from http://mqtt.org/. AMQP: GitHub - Azure/amqpnetlite: AMQP 1.0 .NET Library