Opentelemetry_core.ValueA value in a key/value attribute
val conv :
[< `Bool of bool
| `Float of float
| `Int of int
| `None
| `String of string ] ->
Opentelemetry_core.Common_.Proto.Common.any_value optionval of_otel_opt : Opentelemetry_core.Common_.Proto.Common.any_value option -> t