nl_tokens: Create a capture context similar to sync but without the global state .
pl_tokens: function deferred ( options ) { let args = null ; const promise = new Promise ( ( resolve , reject ) => args = [ resolve , reject , options ] ) ; promise . defer = function defer ( ) { if ( ! args ) throw <mask> Error ( 'defer has already been called' ) ; const callback = callbackBuilder . apply ( undefined , args ) ; args = null ; return callback ; } ; return promise ; }