def micros_to_timestamp(micros, timestamp):
  """Convert microseconds from utc epoch to google.protobuf.timestamp.

  Args:
    micros: a long, number of microseconds since utc epoch.
    timestamp: a google.protobuf.timestamp.Timestamp to populate.
  """
  seconds = long(micros / _MICROS_PER_SECOND)
  micro_remainder = micros % _MICROS_PER_SECOND
  timestamp.seconds = seconds
  timestamp.nanos = micro_remainder * _NANOS_PER_MICRO