Function prefix_end 

pub fn prefix_end(prefix: impl AsRef<[u8]>) -> Option<Vec<u8>>

Return the smallest exclusive upper bound for all keys with prefix.

Returns None when the prefix covers the rest of the keyspace, which is true for the empty prefix and for prefixes made entirely of 0xff bytes.

Example

use prolly::prefix_end;

assert_eq!(prefix_end(b"user/42/"), Some(b"user/420".to_vec()));
assert_eq!(prefix_end(b""), None);