public static async Task<Version> NegotiateVersionWithServer (Stream stream, VersionRange[] supportedVersions)
{
var clientVersion = supportedVersions.First ().UpperBoundInclusive;
await stream.WriteVersionAsync (clientVersion);
var serverVersion = await stream.ReadVersionAsync ();
var negotiatedVersion = DecideWhichVersionToUse (clientVersion, serverVersion);
return negotiatedVersion;
}