*Add support for canceling a streaming query and stop the data stream

src/query/streaming.ts

@@ -9,6 +9,7 @@ import { StreamingRpcQueryOptions } from "../types.js";
 
 export default class StreamingRpcQuery extends SimpleRpcQuery {
   protected _options: StreamingRpcQueryOptions;
+  protected _canceled = false;
   constructor(
     network: RpcNetwork,
     relay: string | Buffer,
@@ -18,6 +19,11 @@ export default class StreamingRpcQuery extends SimpleRpcQuery {
     super(network, relay, query, options);
     this._options = options;
   }
+
+  public cancel() {
+    this._canceled = true;
+  }
+
   protected async queryRelay(relay: string | Buffer): Promise<any> {
     let socket: any;
 
@@ -41,11 +47,25 @@ export default class StreamingRpcQuery extends SimpleRpcQuery {
     }
     return new Promise((resolve, reject) => {
       let timer: any;
+
+      const finish = () => {
+        relay = relay as string;
+        this._responses[relay] = {};
+        resolve(null);
+        socket.end();
+      };
+
       socket.on("data", (res: Buffer) => {
         relay = relay as string;
         if (timer && timer.close) {
           clearTimeout(timer as any);
         }
+
+        if (this._canceled) {
+          finish();
+          return;
+        }
+
         const response = unpack(res as any) as RPCResponse;
         if (response && response.error) {
           this._errors[relay] = response.error;
@@ -53,9 +73,7 @@ export default class StreamingRpcQuery extends SimpleRpcQuery {
         }
 
         if (response?.data.done) {
-          this._responses[relay] = {};
-          resolve(null);
-          socket.end();
+          finish();
           return;
         }