/// <summary>
/// Request Metadata from broker.
///
/// Parameters:
/// allTopics - if true: request info about all topics in cluster,
/// if false: only request info about locally known topics.
/// onlyForTopic - only request info about this topic
/// includeInternal - include internal topics prefixed with __
/// timeout - maximum response time before failing.
/// </summary>
public Task <Metadata> Metadata(bool allTopics = true, Topic onlyForTopic = null,
bool includeInternal = false, TimeSpan timeout = default(TimeSpan))
=> Task.FromResult(handle.Metadata(allTopics, onlyForTopic?.handle, includeInternal, timeout));