saxon:string-to-base64Binary($in as xs:string, $encoding as xs:string) ==> xs:base64Binary
This function takes as input a string and the name of a character
encoding (for example "UTF8"). It encodes the contents of the string value as a sequence of bytes
using a particular encoding, and returns the xs:base64Binary representation
of this sequence of bytes.
For example, the call saxon:string-to-base64Binary("Dassel", "UTF8") returns the
xs:base64Binary value whose lexical representation is "RGFzc2VsIA==".
