README.md: add IPv4 header complex structure notes

diff --git a/README.md b/README.md
index e7a63081715c1fcecab17ec2f66ab254a1da2611..0153e3609dcc4a4ff43dbcf0b0c485ba70f3b0f2 100644 (file)
--- a/README.md
+++ b/README.md
@@ -665,6 +665,11 @@ struct ipv4_header {
 }
 ```
 
+Although this complex structure has more than ten independant fields,
+the generated C function would only call a 20-byte `memcpy()`, making
+it fast to record. Bits will be unpacked properly and values displayed
+in a human-readable form by the CTF reader thanks to the CTF metadata.
+
 
 #### type aliases