/**
     *  Projects each element of an observable sequence into zero or more buffers.
     *
     *  @param {Mixed} bufferOpeningsOrClosingSelector Observable sequence whose elements denote the creation of new windows, or, a function invoked to define the boundaries of the produced windows (a new window is started when the previous one is closed, resulting in non-overlapping windows).
     *  @param {Function} [bufferClosingSelector] A function invoked to define the closing of each produced window. If a closing selector function is specified for the first parameter, this parameter is ignored.
     *  @returns {Observable} An observable sequence of windows.
     */
    observableProto.buffer = function (bufferOpeningsOrClosingSelector, bufferClosingSelector) {
        return this.window.apply(this, arguments).selectMany(function (x) { return x.toArray(); });
    };