log/field.go
func Uint64(key string, val uint64) Field {
	return Field{
		key:        key,
		fieldType:  uint64Type,
		numericVal: int64(val),
	}
}
func Uint64(key string, val uint64) Field {
	return Field{
		key:        key,
		fieldType:  uint64Type,
		numericVal: int64(val),
	}
}
func Uint64 ( key string , val uint64 ) Field { return Field { key : key , fieldType : uint64Type , numericVal : int64 ( val ) , } }
// Uint64 adds a uint64-valued key:value pair to a Span.LogFields() record
Uint64 adds a uint64 - valued key : value pair to a Span . LogFields () record