First pass of the readme. Lots more to come.

CSHARP-README.txt

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+Readme for the C#/.NET implementation of Protocol Buffers
+
+Copyright 2008 Google Inc.
+http://code.google.com/apis/protocolbuffers/
+and
+http://github.com/jskeet/dotnet-protobufs
+
+(This will eventually be written up into a full tutorial etc.)
+
+Differences with respect to the Java API
+----------------------------------------
+
+Many of the changes are obvious "making it more like .NET", but
+others are more subtle.
+
+o Properties and indexers are used reasonably extensively.
+o newFoo becomes CreateFoo everywhere.
+o Classes are broken up much more - for instance, there are
+  namespaces for descriptors and field accessors, just to make it
+  easier to see what's going on.
+o There's a mixture of generic and non-generic code. This
+  is interesting (at least if you're a language nerd). Java's generics
+  are somewhat different to those of .NET, partly due to type erasure
+  but in other ways too. .NET allows types to be overloaded by the
+  number of generic parameters, but there's no such thing as the
+  "raw" type of a generic type. Combining these two facts, I've
+  ended up with two interfaces for messages, and two for builders -
+  in each case, a non-generic one and a generic one which derives
+  from the generic one. Where the members clash (e.g. IBuilder.Build
+  and IBuilder<TMessage>.Build vary only by return type) the
+  implementations use explicit interface implementation to provide
+  the most useful method in most cases. This is very much like
+  the normal implementation of IEnumerable<T> which extends
+  IEnumerable. As an aside, this becomes a pain when trying to
+  create "the read-only version of this list, whose type I don't
+  know but I know it's a List<something>". Oh for mumble types.
+  
+