Searches the dfs file for the time step index of a time, and returns the zero-based time step index. The time axis of the file must be a calendar type time axis

NOTE: For the non-equidistant time axes, the metod will read the first item in the file for a number of timesteps in random order, performing a binary search in the file data on disc. This will be slow if used many times on the same file.

For the equidistant time axis, the method will calculate the time step index directly without reading data from the file.

Searches the dfs file for the time step index of a time, and returns the zero-based time step index.

NOTE: For the non-equidistant time axes, the metod will read the first item in the file for a number of timesteps in random order, performing a binary search in the file data on disc. This will be slow if used many times on the same file.

For the equidistant time axis, the method will calculate the time step index directly without reading data from the file.