Move queueing channel observer to after packing the struct (#1334)

Author: MaxAake

packages/bolt-connection/src/bolt/bolt-protocol-v1.js

@@ -499,18 +499,17 @@ export default class BoltProtocol {
    * @param {boolean} flush `true` if flush should happen after the message is written to the buffer.
    */
   write (message, observer, flush) {
+    this._lastMessageSignature = message.signature
+    const messageStruct = new structure.Structure(message.signature, message.fields)
+
+    this.packable(messageStruct)()
     const queued = this.queueObserverIfProtocolIsNotBroken(observer)
 
     if (queued) {
       if (this._log.isDebugEnabled()) {
         this._log.debug(`C: ${message}`)
       }
 
-      this._lastMessageSignature = message.signature
-      const messageStruct = new structure.Structure(message.signature, message.fields)
-
-      this.packable(messageStruct)()
-
       this._chunker.messageBoundary()
       if (flush) {
         this._chunker.flush()