Jetty HTTP method NPE:

```
Caused by: java.lang.NullPointerException
at io.jooby.internal.jetty.JettyContext.getMethod(JettyContext.java:139)
at io.jooby.ErrorHandler.errorMessage(ErrorHandler.java:122)
at io.jooby.DefaultContext.sendError(DefaultContext.java:530)
at io.jooby.DefaultContext.sendError(DefaultContext.java:515)
at io.jooby.CoroutineRouter$route$1$$special$$inlined$CoroutineExceptionHandler$1.handleException(CoroutineExceptionHandler.kt:82)
at kotlinx.coroutines.CoroutineExceptionHandlerKt.handleCoroutineException(CoroutineExceptionHandler.kt:25)
... 11 more
```

Author: jknack

TODO

@@ -15,3 +15,15 @@ java.io.IOException: Close org.eclipse.jetty.server.HttpConnection$SendCallback@
 	at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:938)
 	at java.lang.Thread.run(Thread.java:748)
 ```
+
+FeaturedKotlinTest.coroutineNoSuspend:
+async:
+
+```
+	Suppressed: java.io.IOException: Close org.eclipse.jetty.server.HttpConnection$SendCallback@4b406dd7[PROCESSING][i=HTTP/1.1{s=200,h=3,cl=-1},cb=org.eclipse.jetty.server.HttpChannel$SendCallback@e42eadb] in state PROCESSING
+		at org.eclipse.jetty.util.IteratingCallback.close(IteratingCallback.java:428)
+		at org.eclipse.jetty.server.HttpConnection.onClose(HttpConnection.java:510)
+		at org.eclipse.jetty.io.SelectorManager.connectionClosed(SelectorManager.java:345)
+		at org.eclipse.jetty.io.ManagedSelector$DestroyEndPoint.run(ManagedSelector.java:967)
+		... 3 more
+```

modules/jooby-jetty/src/main/java/io/jooby/internal/jetty/JettyContext.java

@@ -91,6 +91,8 @@ public class JettyContext implements DefaultContext {
   private HashMap<String, String> responseCookies;
   private boolean responseStarted;
   private Boolean resetHeadersOnError;
+  private String method;
+  private String pathString;
 
   public JettyContext(Request request, Router router, int bufferSize, long maxRequestSize) {
     this.request = request;
@@ -136,7 +138,10 @@ public JettyContext(Request request, Router router, int bufferSize, long maxRequ
   }
 
   @Nonnull @Override public String getMethod() {
-    return request.getMethod().toUpperCase();
+    if (method == null) {
+      method = request.getMethod().toUpperCase();
+    }
+    return method;
   }
 
   @Nonnull @Override public Route getRoute() {
@@ -149,7 +154,10 @@ public JettyContext(Request request, Router router, int bufferSize, long maxRequ
   }
 
   @Nonnull @Override public String pathString() {
-    return request.getRequestURI();
+    if (pathString == null) {
+      pathString = request.getRequestURI();
+    }
+    return pathString;
   }
 
   @Nonnull @Override public Map<String, String> pathMap() {