perf: optimize varint decoding

docs: update type definitions

types/lib/varint.d.ts

@@ -1,10 +1,44 @@
 export default varint;
 declare namespace varint {
-    function encodeInt(val: number): Buffer;
-    function encodeString(val: string): Buffer;
-    function encodeUShort(val: number): Buffer;
-    function concat(chunks: Buffer[]): Buffer;
-    function decodeInt(buffer: Buffer, offset: number): number;
-    function decodeString(val: Buffer, offset?: number): string;
-    function decodeLength(val: number): 5 | 7 | 8 | 1 | 2 | 3 | 4 | 6 | 9 | 10;
+	/**
+	 * Encodes an integer value into a varint byte buffer.
+	 * @param val - The integer value to encode.
+	 */
+	function encodeInt(val: number): Buffer;
+
+	/**
+	 * Encodes a string value into a UTF-8 byte buffer.
+	 * @param val - The string value to encode.
+	 */
+	function encodeString(val: string): Buffer;
+
+	/**
+	 * Encodes an unsigned short value into a byte buffer.
+	 * @param val - The unsigned short value to encode.
+	 */
+	function encodeUShort(val: number): Buffer;
+
+	/**
+	 * Concatenates multiple byte buffers into a single byte buffer.
+	 * @param chunks - An array of byte buffers to concatenate.
+	 */
+	function concat(chunks: Buffer[]): Buffer;
+
+	/**
+	 * Decodes a varint integer value from a buffer.
+	 * @param buffer - The byte buffer to decode from.
+	 * @param offset - The offset in the buffer to start decoding from.
+	 */
+	function decodeInt(buffer: Buffer, offset: number): number;
+
+	/**
+	 * Calculates how many bytes are needed to encode a number as a VarInt.
+	 * VarInts use a variable number of bytes to efficiently encode integers.
+	 * Each byte uses 7 bits for the value and 1 bit to indicate if more bytes follow.
+	 * VarInts are never longer than 5 bytes.
+	 *
+	 * @param val - The number to calculate the VarInt length for.
+	 * @returns The number of bytes needed to encode the value (1-5).
+	 */
+	function decodeLength(val: number): 1 | 2 | 3 | 4 | 5;
 }