message: Improved language: "in micro second" -> "in microseconds"
  Microsecond is the correct word:
  I would suggest plural here, since these are not happening in a microsecond, these are specified in microseconds.
diff: @@ -514,9 +514,9 @@ void producer_plugin::set_program_options(
  ("greylist-account", boost::program_options::value<vector<string>>()->composing()->multitoken(),
  "account that can not access to extended CPU/NET virtual resources")
  ("produce-time-offset-us", boost::program_options::value<int32_t>()->default_value(0),
  - "offset of non last block producing time in micro second. Negative number results in blocks to go out sooner, and positive number results in blocks to go out later")
  + "offset of non last block producing time in microseconds. Negative number results in blocks to go out sooner, and positive number results in blocks to go out later")
  ("last-block-time-offset-us", boost::program_options::value<int32_t>()->default_value(0),
  - "offset of last block producing time in micro second. Negative number results in blocks to go out sooner, and positive number results in blocks to go out later")
  + "offset of last block producing time in microseconds. Negative number results in blocks to go out sooner, and positive number results in blocks to go out later")
  ("incoming-defer-ratio", bpo::value<double>()->default_value(1.0),
  "ratio between incoming transations and deferred transactions when both are exhausted")
  ;
  