current speed: 38 mph
 key   0:0                          
 key   0:13  ^-----------^          current speed
pair   0:13  ^-----------^          current speed
 key  15:15                ^        
 num  15:17                 ^^      38
pair  15:17                 ^^      38
msg         :current speed: 38 mph
format      :#: # mph
{
    "col_0": "current speed",
    "col_1": 38
}