/// <summary>
/// Post event document using processing Route obtained from EventDocument instance and
/// serializing document using json. The content type header is not set by this method.
/// Note: When returned WriteResult does not satisfy caller requirements, this method does NOT
/// give caller a chance to re-post the SAME raw <see cref="Event"/> instance as the onus
/// of failure handling is on the caller.
/// You can use <see cref="GetRawEventForDocument(IEventProducer, EventDocument, JsonDataMap)"/>
/// if you want to re-post the SAME event instance
/// </summary>
/// <param name="producer">Producer to post event into</param>
/// <param name="evtDoc">EventDocument-derivative instance</param>
/// <param name="headers">Event headers or null</param>
/// <param name="lossMode">Data loss mode, if null then default used from doc declaration</param>
/// <returns>WriteResult - how many nodes tried/succeeded/failed</returns>
public static async Task <WriteResult> PostEventDocumentAsync(this IEventProducer producer,
EventDocument evtDoc,
JsonDataMap headers = null,
DataLossMode?lossMode = null)
{
var(attr, partition, rawEvent) = GetRawEventForDocument(producer, evtDoc, headers);
var result = await producer.PostAsync(attr.Route, partition, rawEvent, lossMode ?? attr.LossMode).ConfigureAwait(false);
return(result);
}