Method is_timestamp

cpp/src/parquet/types.cc:831–833

bool LogicalType::is_date() const { return impl_->type() == LogicalType::Type::DATE; }
bool LogicalType::is_time() const { return impl_->type() == LogicalType::Type::TIME; }
bool LogicalType::is_timestamp() const {
  return impl_->type() == LogicalType::Type::TIMESTAMP;
}
bool LogicalType::is_interval() const {
  return impl_->type() == LogicalType::Type::INTERVAL;
}