Are cumulative numpy functions available for Dask Arrays?

It does not appear that the cumulative functions, e.g., np.cumsum, are available: https://github.com/blaze/dask/blob/master/dask/array/core.py#L1052-L1179 for dask Arrays. Is there a particular reason why this is the case? I'd like to be able to do computations of the form

import dask.array as da                     
import numpy as np                          
x = da.from_array(np.random.rand(10,10),chunks=(2,5))  
x.cumsum(axis=1)                                  

Currently this does not appear to be supported.