stream[@@can.offKeyValue](key, handler)

can-reflect.offKeyValue will use this function to stop listening to when emitted values or errors change.

import Kefir from "can-kefir";

const count = Kefir.sequentially( 1000, [ 1, 2, 2, 3 ] );

function handler( newVal ) {
    console.log( "new value", newVal ); // logs 1, 2
    if ( newVal > 2 ) {
        canReflect.offKeyValue( stream, "value", handler );
    }
}

canReflect.onKeyValue( stream, "value", handler );