Thin wrapper for Rx's observer

using System;

namespace Foo
{
    /// <summary>
    /// An abstract base class of classes that observes one or more subject(s) by using Reactive Extensions (Rx).
    /// </summary>
    public abstract class ObserverBase : IDisposable
    {
        private IDisposable _subscription;

        /// <summary>
        /// Starts observing subject(s).
        /// </summary>
        public void StartObserving()
        {
            StopObserving(); // Ensure the previous subscription is disposed.

            _subscription = SubscribeToObservable();
        }

        /// <summary>
        /// Subscribes to observable subject(s).
        /// </summary>
        /// <returns>
        /// The subscription(s). Typically, the disposable returned from the Subscribe extension method of
        /// <seealso cref="IObservable{T}"/> should be returned.
        /// </returns>
        protected abstract IDisposable SubscribeToObservable();

        /// <summary>
        /// Stops observing the subject(s).
        /// If no subject(s) are observed currently, this method does nothing.
        /// </summary>
        public void StopObserving()
        {
            if (_subscription != null)
            {
                _subscription.Dispose();
                _subscription = null;
            }
        }

        /// <summary>
        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
        /// </summary>
        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        /// <summary>
        /// Releases unmanaged and - optionally - managed resources.
        /// </summary>
        /// <param name="disposing">
        /// <c>true</c> to release both managed and unmanaged resources;
        /// <c>false</c> to release only unmanaged resources.
        /// </param>
        protected virtual void Dispose(bool disposing)
        {
            if (disposing)
            {
                StopObserving();
            }
        }
    }
}