update

README.md

@@ -356,7 +356,7 @@ const env = await smartsend(
 ```julia
 using NATSBridge
 
-env = NATSBridge.smartsend(
+env, msg_json_str = NATSBridge.smartsend(
     subject;                           # NATS subject
     data::AbstractArray{Tuple{String, Any, String}};  # List of (dataname, data, type)
     nats_url::String = "nats://localhost:4222",
@@ -371,6 +371,9 @@ env = NATSBridge.smartsend(
     reply_to::String = "",
     reply_to_msg_id::String = ""
 )
+# Returns: (msgEnvelope_v1, JSON string)
+# - env: msgEnvelope_v1 object with all envelope metadata and payloads
+# - msg_json_str: JSON string representation of the envelope for publishing
 ```
 
 ### smartreceive
@@ -636,19 +639,24 @@ data = [("students", df, "table")]
 NATSBridge.smartsend("/data/analysis", data)
 ```
 
-### Example 4: Request-Response Pattern
+### Example 4: Request-Response Pattern with Envelope JSON
 
-Bi-directional communication with reply-to support.
+Bi-directional communication with reply-to support. The `smartsend` function now returns both the envelope object and a JSON string that can be published directly.
 
 #### Python/Micropython (Requester)
 ```python
 from nats_bridge import smartsend
 
-env = smartsend(
+env, msg_json_str = smartsend(
     "/device/command",
     [("command", {"action": "read_sensor"}, "dictionary")],
     reply_to="/device/response"
 )
+# env: msgEnvelope_v1 object
+# msg_json_str: JSON string for publishing to NATS
+
+# The msg_json_str can also be published directly using NATS request-reply pattern
+# nc.request("/device/command", msg_json_str, reply_to="/device/response")
 ```
 
 #### Python/Micropython (Responder)