The boundary "eats" exceptions

[ghost]

When using sync blocks, exceptions in the sync block are eaten by the boundary. It'd be much better to catch those and throw them back at user next time sync blocks are used on the same context.

[txdv]

Or lets wait for C# 5.0! No, seriously, this is an issue :) Action<Exception> !

[ghost]

Unfortunately, no. The exception inside the boundary must propagate out of the context thread, to the person that called into the boundary. Action can't do that. Firing the callback on the next call into the boundary works, of course, but that's inferior to just throwing the exception outright.