microseconds

Input

Dataset[ {
  <| "A" -> "a1", "B" -> "b1", 
  "C" -> { <| "event1" -> 1234, "microseconds" -> 102 |>, <| 
     "event1" -> 4982, "microseconds" -> 3207 |>}, 
  "D" -> { <| "exp" -> 1, "microseconds" -> 103 |>, <| "exp" -> 2, 
     "microseconds" -> 3208 |>} |>,
  <| "A" -> "a2", "B" -> "b2", 
  "C" -> { <| "event1" -> 1234, "microseconds" -> 456 |>, <| 
     "event1" -> 4982, "microseconds" -> 7819 |>},  
  "E" -> { <| "exp" -> 1, "microseconds" -> 9, "size" -> 5 |>, <| 
     "exp" -> 2, "microseconds" -> 18, "size" -> 5 |>}  |>
  } ]

Output

Dataset[ {
   <| "A" -> "a1", "B" -> "b1", 
   "C" -> { <| "event1" -> 1234, 
      "microseconds" -> Quantity[102, "Microseconds"] |>, <| 
      "event1" -> 4982, 
      "microseconds" -> Quantity[3207, "Microseconds"] |>}, 
   "D" -> { <| "exp" -> 1, 
      "microseconds" -> Quantity[103, "Microseconds"] |>, <| 
      "exp" -> 2, 
      "microseconds" -> Quantity[3208, "Microseconds"] |>} |>,
   <| "A" -> "a2", "B" -> "b2", 
   "C" -> { <| "event1" -> 1234, 
      "microseconds" -> Quantity[456, "Microseconds"] |>, <| 
      "event1" -> 4982, 
      "microseconds" -> Quantity[7819, "Microseconds"] |>},  
   "E" -> { <| "exp" -> 1, 
      "microseconds" -> Quantity[9, "Microseconds"], "size" -> 5 |>, <| 
      "exp" -> 2, "microseconds" -> Quantity[18, "Microseconds"], 
      "size" -> 5 |>}  |>
   }]