public void WithMethods()
{
var options = new CallOptions();
var metadata = new Metadata();
Assert.AreSame(metadata, options.WithHeaders(metadata).Headers);
var deadline = DateTime.UtcNow;
Assert.AreEqual(deadline, options.WithDeadline(deadline).Deadline.Value);
var cancellationToken = new CancellationTokenSource().Token;
Assert.AreEqual(cancellationToken, options.WithCancellationToken(cancellationToken).CancellationToken);
var writeOptions = new WriteOptions();
Assert.AreSame(writeOptions, options.WithWriteOptions(writeOptions).WriteOptions);
var propagationToken = new ContextPropagationToken(CallSafeHandle.NullInstance, DateTime.UtcNow,
CancellationToken.None, ContextPropagationOptions.Default);
Assert.AreSame(propagationToken, options.WithPropagationToken(propagationToken).PropagationToken);
var credentials = new FakeCallCredentials();
Assert.AreSame(credentials, options.WithCredentials(credentials).Credentials);
var flags = CallFlags.WaitForReady | CallFlags.CacheableRequest;
Assert.AreEqual(flags, options.WithFlags(flags).Flags);
// Check that the original instance is unchanged.
Assert.IsNull(options.Headers);
Assert.IsNull(options.Deadline);
Assert.AreEqual(CancellationToken.None, options.CancellationToken);
Assert.IsNull(options.WriteOptions);
Assert.IsNull(options.PropagationToken);
Assert.IsNull(options.Credentials);
Assert.AreEqual(default(CallFlags), options.Flags);
}