feat(core): streams (#12596)

This allows resources to be "streams" by implementing read/write/shutdown. These streams are implicit since their nature (read/write/duplex) isn't known until called, but we could easily add another method to explicitly tag resources as streams.

`op_read/op_write/op_shutdown` are now builtin ops provided by `deno_core`

Note: this current implementation is simple & straightforward but it results in an additional alloc per read/write call

Closes #12556

ext/fetch/26_fetch.js

@@ -73,24 +73,6 @@
     return core.opAsync("op_fetch_send", rid);
   }
 
-  /**
-   * @param {number} rid
-   * @param {Uint8Array} body
-   * @returns {Promise<void>}
-   */
-  function opFetchRequestWrite(rid, body) {
-    return core.opAsync("op_fetch_request_write", rid, body);
-  }
-
-  /**
-   * @param {number} rid
-   * @param {Uint8Array} body
-   * @returns {Promise<number>}
-   */
-  function opFetchResponseRead(rid, body) {
-    return core.opAsync("op_fetch_response_read", rid, body);
-  }
-
   // A finalization registry to clean up underlying fetch resources that are GC'ed.
   const RESOURCE_REGISTRY = new FinalizationRegistry((rid) => {
     core.tryClose(rid);
@@ -120,7 +102,8 @@
           // This is the largest possible size for a single packet on a TLS
           // stream.
           const chunk = new Uint8Array(16 * 1024 + 256);
-          const read = await opFetchResponseRead(
+          // TODO(@AaronO): switch to handle nulls if that's moved to core
+          const read = await core.read(
             responseBodyRid,
             chunk,
           );
@@ -260,7 +243,7 @@
           }
           try {
             await PromisePrototypeCatch(
-              opFetchRequestWrite(requestBodyRid, value),
+              core.write(requestBodyRid, value),
               (err) => {
                 if (terminator.aborted) return;
                 throw err;