http2: use more descriptive names

lib/internal/http2/core.js

@@ -582,15 +582,15 @@ function doShutdown(options) {
 function submitShutdown(options) {
   const type = this[kType];
   debug(`Http2Session ${sessionName(type)}: submitting shutdown request`);
-  const fn = doShutdown.bind(this, options);
+  const shutdownFn = doShutdown.bind(this, options);
   if (type === NGHTTP2_SESSION_SERVER && options.graceful === true) {
     // first send a shutdown notice
     this[kHandle].shutdownNotice();
     // then, on flip of the event loop, do the actual shutdown
-    setImmediate(fn);
+    setImmediate(shutdownFn);
     return;
   }
-  fn();
+  shutdownFn();
 }
 
 function finishSessionDestroy(socket) {
@@ -877,12 +877,12 @@ class Http2Session extends EventEmitter {
     debug(`Http2Session ${sessionName(this[kType])}: sending settings`);
 
     state.pendingAck++;
-    const fn = submitSettings.bind(this, settings);
+    const settingsFn = submitSettings.bind(this, settings);
     if (state.connecting) {
-      this.once('connect', fn);
+      this.once('connect', settingsFn);
       return;
     }
-    fn();
+    settingsFn();
   }
 
   // Destroy the Http2Session
@@ -968,14 +968,14 @@ class Http2Session extends EventEmitter {
       this.on('shutdown', callback);
     }
 
-    const fn = submitShutdown.bind(this, options);
+    const shutdownFn = submitShutdown.bind(this, options);
     if (state.connecting) {
-      this.once('connect', fn);
+      this.once('connect', shutdownFn);
       return;
     }
 
     debug(`Http2Session ${sessionName(type)}: sending shutdown`);
-    fn();
+    shutdownFn();
   }
 
   _onTimeout() {
@@ -1379,12 +1379,12 @@ class Http2Stream extends Duplex {
     if (code < 0 || code > kMaxInt)
       throw new errors.RangeError('ERR_OUT_OF_RANGE', 'code');
 
-    const fn = submitRstStream.bind(this, code);
+    const rstStreamFn = submitRstStream.bind(this, code);
     if (this[kID] === undefined) {
-      this.once('ready', fn);
+      this.once('ready', rstStreamFn);
       return;
     }
-    fn();
+    rstStreamFn();
   }
 
   rstWithNoError() {
@@ -1415,12 +1415,12 @@ class Http2Stream extends Duplex {
     options = Object.assign({}, options);
     validatePriorityOptions(options);
 
-    const fn = submitPriority.bind(this, options);
+    const priorityFn = submitPriority.bind(this, options);
     if (this[kID] === undefined) {
-      this.once('ready', fn);
+      this.once('ready', priorityFn);
       return;
     }
-    fn();
+    priorityFn();
   }
 
   // Called by this.destroy().