fix(smartduplex): Enhance documentation for read function in SmartDuplex

ts/smartstream.classes.smartduplex.ts

@@ -56,6 +56,10 @@ export class SmartDuplex<TInput = any, TOutput = any> extends Duplex {
     readableStream: ReadableStream<T>
   ): SmartDuplex<T, T> {
     const smartDuplex = new SmartDuplex<T, T>({
+      /**
+       * this function is called whenever the stream is being read from and at the same time if nothing is enqueued
+       * therefor it is important to always unlock the reader after reading
+       */
       readFunction: async () => {
         const reader = readableStream.getReader();
         const { value, done } = await reader.read();