Merge pull request #2211 from minrk/datapub add data publication message Functions just like displaypub, but sends a namespace of actual data instead of representations. This uses the serialization/zero-copy machinery of the parallel code. The current interpretation of a sequence of data publications within a cell is updates of a single namespace. That is, a series of calls to publish_data(dict(A=...)) during a given cell will result in a single dict with the latest value of A, updated in-place. An alternate interpretation could be to keep appending to a list, but I expect the current update approach to be preferable. Changes along the way: AsyncResults no longer protect metadata access while results are pending. This was an artificial limitation, and impedes informed access of incomplete metadata, which actually works just fine.