Remove mmap-io which constantly causing issues

lib/prediction/exact.ts

@@ -85,25 +85,7 @@ export default class ExactMatcher {
     }
 
     async load(filename : string) {
-        let buffer;
-        try {
-            const mmap = (await import('mmap-io')).default;
-            const fd = await pfs.open(filename, 'r');
-            const stats = await fd.stat();
-            buffer = mmap.map(Math.ceil(stats.size / mmap.PAGESIZE) * mmap.PAGESIZE,
-                mmap.PROT_READ, mmap.MAP_SHARED | mmap.MAP_POPULATE, fd.fd, 0, mmap.MADV_RANDOM);
-
-            // we created the mapping, so we can close the file and remove it - the kernel
-            // keeps a reference to it
-            // at the next load, we'll overwrite _btrie, which will cause the buffer to go unreferenced
-            // later, the GC will release buffer, unmap it, and _only then_ will the file actually be
-            // closed and deleted
-            await fd.close();
-        } catch(e) {
-            if (e.code !== 'MODULE_NOT_FOUND')
-                throw e;
-            buffer = await pfs.readFile(filename);
-        }
+        const buffer = await pfs.readFile(filename);
         this._btrie = new BTrie(buffer);
 
         // assume that the binary file contains all modifications made afterwards, and clear the trie

package.json

@@ -33,7 +33,6 @@
     "js-yaml": "^4.1.0",
     "lice-js": "^0.2.0",
     "mime": "^3.0.0",
-    "mmap-io": "^1.1.7",
     "morgan": "^1.9.1",
     "node-gettext": "^3.0.0",
     "nodemailer": "^6.7.2",