module Type:sig..end
type 'a t 
The type for a user event content type.
val unit : unit tAn event that has no data associated with it.
type span = 
| | 
Begin | 
| | 
End | 
val span : span tAn event that has a beginning and an end.
val int : int tAn event containing an integer value.
val register : encode:(bytes -> 'a -> int) ->
       decode:(bytes -> int -> 'a) -> 'a tRegisters a custom type by providing an encoder and a decoder. The encoder writes the value in the provided buffer and returns the number of bytes written. The decoder gets a slice of the buffer of specified length, and returns the decoded value.
The maximum value length is 1024 bytes.