/// <summary>
/// Begins an asynchronous operation to send the specified
/// <see cref="AK.Net.Dns.DnsQuery"/> to the specified end point
/// and return the <see cref="AK.Net.Dns.DnsReply"/>.
/// </summary>
/// <param name="query">The query to send.</param>
/// <param name="endpoint">The transport end point.</param>
/// <param name="callback">The method to invoke once the asynchronous operation
/// has completed.</param>
/// <param name="state">The user-defined state object to associate with the
/// asynchronous operation.</param>
/// <returns>The asynchronous operation result.</returns>
/// <exception cref="System.ArgumentNullException">
/// Thrown when <paramref name="query"/>, <paramref name="endpoint"/> or
/// <paramref name="callback"/> is <see langword="null"/>.
/// </exception>
public virtual IAsyncResult BeginSend(DnsQuery query, IPEndPoint endpoint,
AsyncCallback callback, object state)
{
Guard.NotNull(endpoint, "endpoint");
Guard.NotNull(callback, "callback");
SendAsyncState asyncState = new SendAsyncState(callback, state);
asyncState.QueueOperation(delegate {
try {
asyncState.Result = Send(query, endpoint);
} catch (DnsTransportException exc) {
asyncState.Exception = exc;
} finally {
asyncState.OnComplete();
}
});
return(asyncState);
}