require(["webjars/ace/1.3.3/src/ace"], function() {
			require(["xtext/xtext-ace"], function(xtext) {
				
				var cs = xtext.createServices;
				if (cs) {
					xtext.createServices = function(editor, options) {
						const s = cs.call(this, editor, options);
						for (const property in s) {
							const oldSendRequest = s[property].sendRequest;
							if (oldSendRequest) {
								 editor.xtextServices[property].sendRequest = function(editorContext, settings, needsSession) {
								 	self = this;
								 	settings.data.dullydully="Hello";
								 	oldSendRequest.call(self, editorContext, settings, needsSession);
								 }
							}
						}
						return s;
					}
				}
			
				var editor = xtext.createEditor({
					baseUrl: baseUrl,
					syntaxDefinition: "xtext-resources/generated/mode-mydsl"
				});
				
			});
		});

//assuming this does not strip anything, otherwise maybe call original beforeSend
settings.beforeSend = function(xhr){xhr.setRequestHeader('X-Test-Header', 'test-value');};

$.ajaxSetup({
				    beforeSend: function(xhr) {
				        xhr.setRequestHeader('X-Test-Header', '...');
				    }
				});