Writing egg files from psyllid fails

[laroque]

To reproduce, run the attached config files (remove the extra .txt extension required by github for upload), with a local egg file (match the egg file's name to the path in the config files).

psyllid_egg_reader_mask_only.yaml.txt
psyllid_egg_reader_trigger_only.yaml.txt

[laroque]

We've determined that the problem in the second file is that libhdf5 is inherently not thread safe (even when working with different files). This configuration has two threads, one ready an input egg and another writing an output egg. To deal with this:

• we can add the --enable-threadsafe flag, but this is an unsupported configuration (combining with --enable-cxx). There's a flag to override that, with it on it appears to work but we haven't tested very far.
• we discussed adding a global mutex in monarch to provide threadsafety around all hdf5 interactions
• the most extreme option would be to rewrite monarch to use only the lower-level C interface (instead of the much more convenient C++ interface); this seems like significant work and we don't currently have a plan to do it.