Nesting Struct Support for Supported Types #957

Certain types, many stdlib (e.g. a net/netip.Prefix) implement a:

• encoding.BinaryMarshaler
• encoding.BinaryUnmarshaler
• encoding.TextMarshaler
• encoding.TextUnmarshaler

These interfaces, notably encoding.TextUnmarshaler/encoding.TextMarshaler, should most likely be used where the DB field type supports it.

For example:

package main

import (
    `net/netip`
)

type MyStruct struct {
    ID uint `db:"id"`
    Network netip.Prefix `db:"net"`
}

Preparing a named statement for this passes just fine (if nmStmt, err = db.PrepareNamed("INSERT INTO someTbl (id, net) VALUES (:id, :net);"); err != nil {...).

However, upon actually trying to execute it (if res, err = nmStmt.Exec(&MyStruct{ID: 3, Network: netip.MustParsePrefix("192.168.1.0/24")}); err != nil {...), the execution will fail with an unsupported type netip.Prefix, a struct error.

Even if the target column data type is a SQLite TEXT.

Now, because this is stdlib, I'd have to coerce type it, which leads to a lot of what is probably unnecessary code because this is a stdlib type that indicates that it can both marshal and unmarshal itself to/from both text and bytes.

Does sqlx do any sort of on-the-fly marshaling/unmarshaling like that, or is this likely instead an issue with the driver (in this case, the recommended github.com/mattn/go-sqlite3 per here)?