Bin.Sizetype 'a t = private | Static of int| Dynamic of 'a| UnknownA value representing information known about the length in bytes of encodings produced by a particular binary codec:
Static n: all encodings produced by this codec have length n;Dynamic fn: the length of binary encodings is dependent on the specific value, but may be efficiently computed at run-time via the function fn;Unknown: this codec may produce encodings that cannot be efficiently pre-computed.