Python promises
copied from cf-staging / vineconda install conda-forge::vine
conda install conda-forge/label/cf201901::vine
conda install conda-forge/label/cf202003::vine
conda install conda-forge/label/gcc7::vine
This is a special implementation of promises in that it can be used both for promise of a value and lazy evaluation. The biggest upside for this is that everything in a promise can also be a promise, e.g. filters, callbacks and errbacks can all be promises.