/// <summary>Tries to receive a message from the queue, which may complete synchronously or asynchronously if no message is ready</summary>
/// <param name="properties">The properties to read</param>
/// <param name="timeout">The time allowed, defaults to infinite. Use <see cref="F:System.TimeSpan.Zero" /> to return without waiting</param>
/// <returns>The a task that contains a message, or a task will a null Result if the receive times out</returns>
public async Task <Message> ReadAsync(Properties properties, TimeSpan?timeout = default(TimeSpan?))
{
for (;;)
{
var msg = await _queueReader.ReadAsync(properties | Properties.Label, timeout);
var hash = ComputeHash(msg);
var existingHash = _hashByLabel[msg.Label];
if (hash == existingHash)
{
Console.Error.WriteLine($"Dropping duplicate message for label '{msg.Label}'");
continue;
}
_hashByLabel[msg.Label] = hash;
return(msg);
}
}
