Constant lmdb::WRITE_MAP

pub const WRITE_MAP: EnvironmentFlags = EnvironmentFlags{bits: MDB_WRITEMAP,}

Use a writeable memory map unless READ_ONLY is set. This is faster and uses fewer mallocs, but loses protection from application bugs like wild pointer writes and other bad updates into the database. Incompatible with nested transactions. Processes with and without WRITE_MAP on the same environment do not cooperate well.