Use .buffer to comply with buffer@4 and browserify@13

Author: okdistribute

lib/request.js

@@ -96,7 +96,7 @@ ClientRequest.prototype._onFinish = function () {
 	if (opts.method === 'POST' || opts.method === 'PUT' || opts.method === 'PATCH') {
 		if (capability.blobConstructor) {
 			body = new global.Blob(self._body.map(function (buffer) {
-				return buffer.toArrayBuffer()
+				return buffer.buffer
 			}), {
 				type: (headersObj['content-type'] || {}).value || ''
 			})