qualified:name: foo=1 bar=2
 key   0:0                                
word   0:9   ^-------^                    qualified
 val   0:9   ^-------^                    qualified
pair   0:9   ^-------^                    qualified
 key  10:10           ^                   
word  10:14            ^--^               name
 val  10:14            ^--^               name
pair  10:14            ^--^               name
 key  16:19                  ^-^          foo
 num  20:21                      ^        1
 val  20:21                      ^        1
pair  16:21                  ^---^        foo=1
 key  22:25                        ^-^    bar
 num  26:27                            ^  2
 val  26:27                            ^  2
pair  22:27                        ^---^  bar=2
msg         :qualified:name: foo=1 bar=2
format      :#:#: foo=# bar=#
{
    "col_0": "qualified",
    "col_1": "name",
    "foo": 1,
    "bar": 2
}