You cannot have multiple writers to a SQLite database. Only a single file descriptor may be open with 'write' access. As long as you can get the performance you need out of a single writer, then you're good!
Clarification: You can have multiple connections (aka file descriptors) open on the same database file for writing at the same time. But only one can be actively writing at a time. SQLite uses file locking to serialize writes. Multiple writers can exist concurrently, they merely have to take turns writing.