Function url_encoded 

pub fn url_encoded(input: &[u8]) -> String

Implements percent-encoding of byte arrays. It is not suggested, despite it’s public access, that you use this function. Instead, feed the byte array directly to the member data for the type you wish to have encoded, it will do it automatically on output.

Encode portions of the URL according to https://www.w3.org/TR/did-core/#did-syntax