TODO: improve code for large MQTT payloads
Closes #19416
diff --git a/docs/TODO b/docs/TODO
index add6819..99e8d1d 100644
--- a/docs/TODO
+++ b/docs/TODO
@@ -180,6 +180,7 @@
21.1 Support rate-limiting
21.2 Support MQTTS
21.3 Handle network blocks
+ 21.4 large payloads
22. TFTP
22.1 TFTP does not convert LF to CRLF for mode=netascii
@@ -1270,16 +1271,24 @@
21.3 Handle network blocks
- Running test suite with
- `CURL_DBG_SOCK_WBLOCK=90 ./runtests.pl -a mqtt` makes several
- MQTT test cases fail where they should not.
+ Running test suite with `CURL_DBG_SOCK_WBLOCK=90 ./runtests.pl -a mqtt` makes
+ several MQTT test cases fail where they should not.
+
+21.4 large payloads
+
+ libcurl unnecessarily allocates heap memory to hold the entire payload to get
+ sent, when the data is already perfectly accessible where it is when
+ `CURLOPT_POSTFIELDS` is used. This is highly inefficient for larger payloads.
+ Additionally, libcurl does not support using the read callback for sending
+ MQTT which is yet another way to avoid having to hold large payload in
+ memory.
22. TFTP
22.1 TFTP does not convert LF to CRLF for mode=netascii
- RFC 3617 defines that an TFTP transfer can be done using "netascii"
- mode. curl does not support extracting that mode from the URL nor does it treat
+ RFC 3617 defines that an TFTP transfer can be done using "netascii" mode.
+ curl does not support extracting that mode from the URL nor does it treat
such transfers specifically. It should probably do LF to CRLF translations
for them.
