ExpectContinuePolicy
using Azure.Core;
using Azure.Core.Pipeline;
namespace Azure.Storage
{
    internal class ExpectContinuePolicy : HttpPipelineSynchronousPolicy
    {
        public long ContentLengthThreshold { get; set; }
        public override void OnSendingRequest(HttpMessage message)
        {
            if (message.Request.Content != null && !CompatSwitches.DisableExpectContinueHeader && (!message.Request.Content.TryComputeLength(out long length) || length >= ContentLengthThreshold))
                message.Request.Headers.SetValue("Expect", "100-continue");
        }
    }
}