Update release notes for PR #122

Author: ponylang-main

.release-notes/add-copy-out.md

@@ -466,3 +466,31 @@ actor MyNotify is SessionStatusNotify
 
 The callback has a default no-op implementation, so existing code is unaffected.
 
+## Add COPY TO STDOUT support
+
+You can now bulk-export data from PostgreSQL using `COPY ... TO STDOUT`. Call `session.copy_out()` with a COPY SQL statement and a `CopyOutReceiver` to start the operation. The server drives the flow — data arrives via `pg_copy_data` callbacks, and `pg_copy_complete` fires when all data has been delivered.
+
+```pony
+actor Exporter is (SessionStatusNotify & ResultReceiver & CopyOutReceiver)
+  var _buffer: Array[U8] iso = recover iso Array[U8] end
+
+  be pg_session_authenticated(session: Session) =>
+    session.copy_out("COPY my_table TO STDOUT", this)
+
+  be pg_copy_data(session: Session, data: Array[U8] val) =>
+    _buffer.append(data)
+
+  be pg_copy_complete(session: Session, count: USize) =>
+    let received = String.from_iso_array(
+      _buffer = recover iso Array[U8] end)
+    _env.out.print("Exported " + count.string() + " rows")
+    _env.out.print(received)
+
+  be pg_copy_failed(session: Session,
+    failure: (ErrorResponseMessage | ClientQueryError))
+  =>
+    // handle error
+```
+
+Data format depends on the COPY command — the default is tab-delimited text with newline row terminators. Data chunks do not necessarily align with row boundaries; the receiver should buffer chunks if row-level processing is needed.
+