*Add a streams api for use with rpc

src/streams.ts

@@ -0,0 +1,33 @@
+function idFactory(start = 1, step = 1, limit = 2 ** 32) {
+  let id = start;
+
+  return function nextId() {
+    const nextId = id;
+    id += step;
+    if (id >= limit) id = start;
+    return nextId;
+  };
+}
+
+export interface StreamFileResponse {
+  data?: Uint8Array;
+  done: boolean;
+}
+
+const nextId = idFactory(1);
+const streams = new Map<number, AsyncIterable<Uint8Array>>();
+
+export function getStream(id: number): AsyncIterable<Uint8Array> | boolean {
+  if (!streams.has(id)) {
+    return false;
+  }
+
+  return streams.get(id) as AsyncIterable<Uint8Array>;
+}
+
+export function addStream(stream: AsyncIterable<Uint8Array>): number {
+  const id = nextId();
+  streams.set(id, stream);
+
+  return id;
+}