DB Write access needs to be protected

[RussellHaley]

Issue
lmdb allows only one writer per environment.
http://www.lmdb.tech/doc/starting.html
"There can be multiple simultaneously active read-only transactions but only one that can write. Once a single read-write transaction is opened, all further attempts to begin one will block until the first one is committed or aborted. This has no effect on read-only transactions, however, and they may continue to be opened at any time."

I am unsure of how lua's single threading affects this limitation, but can conceive that yielding will be problematic. Should the system support multithreading with one environment?

Solution
There needs to be a new write transaction manager created that mutexes the write access and stores it in the lmdb environment wrapper (?).