Adds a way to verify/exposes Entities ids (#7221)

swift/Sources/FlatBuffers/Verifier.swift

@@ -200,4 +200,14 @@ public struct Verifier {
   internal mutating func finish() {
     _depth -= 1
   }
+
+  mutating func verify(id: String) throws {
+    let size = MemoryLayout<Int32>.size
+    let str = _buffer.readString(at: size, count: size)
+    if id == str {
+      return
+    }
+    throw FlatbuffersErrors.bufferIdDidntMatchPassedId
+  }
+
 }