BufWriter implements buffering for an deno.Writer object. If an error occurs writing to a Writer, no more data will be accepted and all subsequent writes, and flush(), will return the error. After all data has been written, the client should call the flush() method to guarantee all data has been forwarded to the underlying deno.Writer.

BufWriterSync implements buffering for a deno.WriterSync object. If an error occurs writing to a WriterSync, no more data will be accepted and all subsequent writes, and flush(), will return the error. After all data has been written, the client should call the flush() method to guarantee all data has been forwarded to the underlying deno.WriterSync.