feat: support custom requestID generation

This feature is to support generating requestID in either a string or
numeric format. Additionally this will support multiple clients
operating against the same context.

The goal here is to allow systems like client generator to
pass through this option to other downstream operators

fixes #277 , fixes #279

src/RequestManager.ts

@@ -11,6 +11,13 @@ export interface IRequestEvents {
   "error": (err: JSONRPCError) => void;
   "notification": (data: any) => void;
 }
+export type RequestID = string | number;
+
+export type INextRequestID = () => RequestID;
+export const defaultNextRequest = () => {
+  let lastId = -1;
+  return () => ++lastId;
+}
 /*
 ** Naive Request Manager, only use 1st transport.
  * A more complex request manager could try each transport.
@@ -25,12 +32,14 @@ class RequestManager {
   private requests: any;
   private batchStarted: boolean = false;
   private lastId: number = -1;
+  private nextID: INextRequestID;
 
-  constructor(transports: Transport[]) {
+  constructor(transports: Transport[], nextID:INextRequestID = defaultNextRequest()) {
     this.transports = transports;
     this.requests = {};
     this.connectPromise = this.connect();
     this.requestChannel = new EventEmitter();
+    this.nextID = nextID;
   }
 
   public connect(): Promise<any> {
@@ -45,7 +54,7 @@ class RequestManager {
   }
 
   public async request(requestObject: JSONRPCMessage, notification: boolean = false, timeout?: number | null): Promise<any> {
-    const internalID = (++this.lastId).toString();
+    const internalID = this.nextID().toString();
     const id = notification ? null : internalID;
     // naively grab first transport and use it
     const payload = {request: this.makeRequest(requestObject.method, requestObject.params || [], id) , internalID};