/// <summary>
/// 尝试获取指定服务的特征。
/// </summary>
/// <typeparam name="TService">指定的服务类型。</typeparam>
/// <param name="register">给定的 <see cref="IServiceCharacteristicsRegister"/>。</param>
/// <param name="result">输出 <see cref="ServiceCharacteristics"/>（如果服务类型的特征不存在，则默认为 <see cref="ServiceCharacteristics.Singleton(bool)"/>）。</param>
/// <returns>返回布尔值。</returns>
public static bool TryGet <TService>(this IServiceCharacteristicsRegister register,
out ServiceCharacteristics result)
=> register.NotNull(nameof(register)).TryGet(typeof(TService), out result);
/// <summary>
/// 获取指定服务的特征或默认特征（如果服务类型的特征不存在，则添加默认 <see cref="ServiceCharacteristics.Singleton(bool)"/>）。
/// </summary>
/// <typeparam name="TService">指定的服务类型。</typeparam>
/// <param name="register">给定的 <see cref="IServiceCharacteristicsRegister"/>。</param>
/// <param name="addIfNone">如果注册器中不存在特征时，是否自行添加（可选；默认添加）。</param>
/// <returns>返回 <see cref="ServiceCharacteristics"/>。</returns>
public static ServiceCharacteristics GetOrDefault <TService>(this IServiceCharacteristicsRegister register,
bool addIfNone = true)
=> register.NotNull(nameof(register)).GetOrDefault(typeof(TService), addIfNone);
/// <summary>
/// 尝试添加指定服务的特征。
/// </summary>
/// <typeparam name="TService">指定的服务类型。</typeparam>
/// <param name="register">给定的 <see cref="IServiceCharacteristicsRegister"/>。</param>
/// <param name="characteristics">给定的 <see cref="ServiceCharacteristics"/>。</param>
/// <returns>返回布尔值。</returns>
public static bool TryAdd <TService>(this IServiceCharacteristicsRegister register,
ServiceCharacteristics characteristics)
=> register.NotNull(nameof(register)).TryAdd(typeof(TService), characteristics);
/// <summary>
/// 添加或设置指定服务的特征。
/// </summary>
/// <typeparam name="TService">指定的服务类型。</typeparam>
/// <param name="register">给定的 <see cref="IServiceCharacteristicsRegister"/>。</param>
/// <param name="characteristics">给定的 <see cref="ServiceCharacteristics"/>。</param>
/// <returns>返回 <see cref="ServiceCharacteristics"/>。</returns>
public static ServiceCharacteristics AddOrSet <TService>(this IServiceCharacteristicsRegister register,
ServiceCharacteristics characteristics)
=> register.NotNull(nameof(register)).AddOrSet(typeof(TService), characteristics);