log/field.go
func Uint32(key string, val uint32) Field {
	return Field{
		key:        key,
		fieldType:  uint32Type,
		numericVal: int64(val),
	}
}
func Uint32(key string, val uint32) Field {
	return Field{
		key:        key,
		fieldType:  uint32Type,
		numericVal: int64(val),
	}
}
// Uint32 adds a uint32-valued key:value pair to a Span.LogFields() record