function IsReadableStreamDefaultReader(x) {
		        if (!typeIsObject(x)) {
		            return false;
		        }
		        if (!Object.prototype.hasOwnProperty.call(x, '_readRequests')) {
		            return false;
		        }
		        return x instanceof ReadableStreamDefaultReader;
		    }
A readable stream represents a source of data, from which you can read.

@public