ConstantStream.js

util.inherits(ConstantStream,stream.Readable);
function ConstantStream(constant){
    stream.Readable.call(this,{objectMode:true});
    this.constant =constant; //get count form Cache
}

ConstantStream.prototype._read = function(){
    var value ={};
    value.name ='constant';
    value.data =this.constant;
    this.push([value]);
};