Extend a pipe until it has a minimum number of elements. If the minimum elements are already present, does nothing.
This is useful if you need a certain number of elements in the pipe before you can process any more data.
The number of elements to ensure are in the window. If omitted, all elements are extended.
The resulting number of elements in the window. This may be less than the requested elements if the pipe ran out of data.
See Implementation
Extend a pipe until it has a minimum number of elements. If the minimum elements are already present, does nothing.
This is useful if you need a certain number of elements in the pipe before you can process any more data.