Protobuf: Compute Timestamp from current time in Ruby

timestamp.proto

// Example lifted from https://github.com/google/protobuf/blob/master/src/google/protobuf/timestamp.proto
//
// Example 6: Compute Timestamp from current time in Ruby
//
//    [1] pry(main)> now = Time.now
//    => 2016-05-20 00:33:04 -0700
//    [2] pry(main)> seconds = now.to_i
//    => 1463729584
//    [3] pry(main)> nanos = now.nsec
//    => 204053000
//    [4] pry(main)> timestamp = Timestamp.new(seconds: seconds, nanos: nanos)
//    => #<Timestamp seconds=1463729584 nanos=204053000>
//    [5] pry(main)> Time.at(timestamp.seconds, timestamp.nanos / 1000)
//    => 2016-05-20 00:33:04 -0700
//    [6] pry(main)> now == _
//    => true

message Timestamp {

  // Represents seconds of UTC time since Unix epoch
  // 1970-01-01T00:00:00Z. Must be from from 0001-01-01T00:00:00Z to
  // 9999-12-31T23:59:59Z inclusive.
  optional int64 seconds = 1;

  // Non-negative fractions of a second at nanosecond resolution. Negative
  // second values with fractions must still have non-negative nanos values
  // that count forward in time. Must be from 0 to 999,999,999
  // inclusive.
  optional int32 nanos = 2;
}