I’m trying to set the content type of an output blob to ‘text/json’ using imperative binding. I’m writing some Azure functions that respond to a service bus trigger by writing some data to a blob, and I need to manually define a filename for my blob output, so I’ve used imperative binding like so:

[FunctionName("Usage")]
        public async Task Run([ServiceBusTrigger("Usage", "UsageFuncProc", Connection = "UsageFunctionsServiceBus")]ServiceBusReceivedMessage sbusMessage,
            Binder binder)
        {
         ...

         var attributes = new Attribute[]{
                new BlobAttribute($"{Utilities.GetContainerName("BlobContainerName")}/{distFormatted}{timestamp}_{entity.ClientId}_{entity.MessageType}.json", FileAccess.Write),
                new StorageAccountAttribute("AzureWebJobsStorage")
            };

            using (var writer = await binder.BindAsync<TextWriter>(attributes)){
                await writer.WriteAsync(jsonEntity);
            }

This works, but by default it saves the content type as ‘application/octet-stream’ – How do I change the content type to ‘text/json’ using imperative binding?