usingcurl/verbose/trace.md: add --trace-config and --trace-ids

Fixes #329
Addresses half of #326
Closes #349

index-words

@@ -78,6 +78,8 @@
 --tr-encoding
 --trace
 --trace-ascii
+--trace-config
+--trace-ids
 --trace-time
 --url-query
 --variable

usingcurl/verbose/trace.md

@@ -57,11 +57,11 @@ first lines of tracing look like:
     <= Recv header, 31 bytes (0x1f)
     0000: Cache-Control: max-age=604800
 
-## --trace-time
+## Time stamps
 
-This options prefixes all verbose/trace outputs with a high resolution timer
-for when the line is printed. It works with the regular `-v / --verbose`
-option as well as with `--trace` and `--trace-ascii`.
+The `--trace-time` option prefixes all verbose/trace outputs with a high
+resolution timer for when the line is printed. It works with the regular `-v /
+--verbose` option as well as with `--trace` and `--trace-ascii`.
 
 An example could look like this:
 
@@ -83,3 +83,48 @@ An example could look like this:
 The lines are all the local time as hours:minutes:seconds and then number of
 microseconds in that second.
 
+## Identify transfers and connections
+
+As the trace information flow showing on screen or to a file using these
+options is a continuous stream even though your command line might make curl
+use a large number of separate connections and different transfers, there are
+times when you want to see to which specific transfers or connections the
+various information below to. To better understand the trace output.
+
+You can then add `--trace-ids` to the line and you will see how curl adds two
+numbers to all tracing: the connection number and the transfer number. They
+are two separate identifiers because connections can be reused and multiple
+transfers can use the same connection.
+
+## More data
+
+If the amount of tracing data is not enough. Like when you suspect and want to
+debug a problem in a more fundamental lower protocol level, curl provides the
+`--trace-config` option for you.
+
+With this option you tell curl to also include logging about components that
+it otherwise does not include by default. Such as details about TLS, HTTP/2 or
+HTTP/3 protocol bits. It also has convenience options for adding the
+connection and transfers identifiers and time stamps.
+
+The `--trace-config` option accepts an argument where you specify a
+comma-separated list with the areas you want it to trace. For example, include
+identifiers and show me HTTP/2 details:
+
+    curl --trace-config ids,http/2 https://example.com
+
+The exact set of ares will vary, but here are some ones to try:
+
+| area     | description                                     |
+|----------|-------------------------------------------------|
+| `ids`    | the same identifiers as `--trace-ids` provides  |
+| `time`   | the same time output as `--trace-time` provides |
+| `all`    | show everything possible                        |
+| `tls`    | TLS protocol exchange details                   |
+| `http/2` | HTTP/2 frame information                        |
+| `http/3` | HTTP/3 frame information                        |
+| `*`      | additional ones in future versions              |
+
+Doing a quick run with `all` is often a good way to get to see which specific
+areas that are shown, as then you can do follow-up runs with more specific
+areas set.