nl_tokens: Buffer all files before parsing them to livingcss .
pl_tokens: function bufferContents ( file , enc , cb ) { // ignore empty files if ( <mask> . isNull ( ) ) { return cb ( ) ; } // no streams if ( file . isStream ( ) ) { this . emit ( 'error' , new PluginError ( 'gulp-livingcss' , 'Streaming not supported' ) ) ; return cb ( ) ; } files . push ( file . path ) ; cb ( ) ; }