A simple test follows:
${message}
<#compress>This is the same message, using the "compress" tag:
${message}
#compress> <@utility.standardCompress buffer_size=8>This is the same message, using the "StandardCompress" transform model:
${message}
@> <@utility.standardCompress single_line=true>This multi-line message should be compressed to a single line.
@>An example where the first character is not whitespace but the second character is:
<#compress>x y#compress>
The end.