add it-length-prefixed types

src/@types/it-length-prefixed/index.d.ts

@@ -0,0 +1,39 @@
+declare module "it-length-prefixed" {
+  /* eslint-disable @typescript-eslint/interface-name-prefix */
+  import BufferList from "bl";
+  import {Buffer} from "buffer"
+
+  interface LengthDecoderFunction {
+    (data: Buffer | BufferList): number;
+    bytes: number;
+  }
+
+  interface LengthEncoderFunction {
+    (value: Buffer, target: number, offset: number): number|Buffer;
+    bytes: number;
+  }
+
+  interface Encoder {
+    (options?: Partial<{lengthEncoder: LengthEncoderFunction}>): AsyncGenerator<BufferList, Buffer>;
+    single: (chunk: Buffer, options?: Partial<{lengthEncoder: LengthEncoderFunction}>) => BufferList;
+    MIN_POOL_SIZE: number;
+    DEFAULT_POOL_SIZE: number;
+  }
+
+  interface DecoderOptions {
+    lengthDecoder: LengthDecoderFunction;
+    maxLengthLength: number;
+    maxDataLength: number;
+  }
+
+  interface Decoder {
+    (options?: Partial<DecoderOptions>): AsyncGenerator<BufferList, BufferList>;
+    fromReader: (reader: any, options?: Partial<DecoderOptions>) => BufferList;
+    MAX_LENGTH_LENGTH: number;
+    MAX_DATA_LENGTH: number;
+  }
+
+  export const encode: Encoder;
+  export const decode: Decoder;
+
+}