mongoose/docs/c-api/mbuf.h/mbuf_insert.md

title	decl_name	symbol_kind	signature
mbuf_insert()	mbuf_insert	func	size_t mbuf_insert(struct mbuf *, size_t, const void *, size_t);

Inserts data at a specified offset in the Mbuf.

Existing data will be shifted forwards and the buffer will be grown if necessary. Returns the number of bytes inserted.