Generic.EqualCustom equality key.
The Fun.Generic.equal function consults this key in the metadata of a gist g before determining equality between values described by the gist. If a function is found, the values are compared with this function instead.
This can also be used to indicate that you would not like to compare a subtructure by always returning true with Equal.ignore.
val ignore : 'a tignore v0 v1 is true.
val mem : ('a, 'b) Type.Gist.Meta.t2 -> boolval add : 'a t -> ('a, 'b) Type.Gist.Meta.t2 -> ('a, 'b) Type.Gist.Meta.t2val find : ('a, 'b) Type.Gist.Meta.t2 -> 'a t optionval remove : ('a, 'b) Type.Gist.Meta.t2 -> ('a, 'b) Type.Gist.Meta.t2