I am currently trying to iterate over a storage map over multiple blocks. For this I need to ensure that the
StorageMap was not modified.
My plan is to derive a hash from the current
StorageMap and save that hash in another storage item in order to check if the new call in the next block has the same
StorageMap state as the previous call. So, I derive the hash of the
StorageMap again and check for equality.
If the hashes are equal, I can use
StorageMap::iter_from(raw_key), otherwise I return an error and request the user to call the multi-block execution again.
So: How can I derive a hash for the current StorageMap state?