current speed: 38 mph
 key   0:13  ^-----------^          current speed
 num  15:17                 ^^      38
 val  15:17                 ^^      38
pair   0:17  ^---------------^      current speed: 38
 key  18:18                   ^     
word  18:21                    ^-^  mph
 val  18:21                    ^-^  mph
pair  18:21                    ^-^  mph
msg         :current speed: 38 mph
format      :current speed: # #
{
    "current speed": 38,
    "col_0": "mph"
}