LIMA (Reuters) - Socialist Peruvian presidential candidate Pedro Castillo has edged ahead of rival Keiko Fujimori in a fast count of the Peruvian presidential run-off with 50.2% to her 49.8%. The result, with a 1% margin of error, comes after an Ipsos Peru exit poll issued three hours earlier suggested Fujimori had 50.3% of the vote share to Castillo’s 49.7%. Reporting by Marco Aquino in Lima, Marcelo Rochabrun in Tacabamba, writing by Aislinn Laing; Editing by Christian Schmollinger Our Standards: The Thomson Reuters Trust Principles.