fix: close stream after sending identify (#1424)

Close the stream after we finish writing the identify message. This is behavior is specified https://github.com/libp2p/specs/blob/master/identify/README.md#identify

> The peer being identified responds by returning an Identify message and closes the stream.

This shows up when interacting with a go-libp2p node as go-libp2p waits for the stream to close before finishing reading the messages: https://github.com/libp2p/go-libp2p/blob/master/p2p/protocol/identify/id.go#L455.

src/identify/index.ts

@@ -2,7 +2,6 @@ import { logger } from '@libp2p/logger'
 import errCode from 'err-code'
 import * as lp from 'it-length-prefixed'
 import { pipe } from 'it-pipe'
-import drain from 'it-drain'
 import first from 'it-first'
 import { fromString as uint8ArrayFromString } from 'uint8arrays/from-string'
 import { multiaddr, protocols } from '@multiformats/multiaddr'
@@ -191,16 +190,14 @@ export class IdentifyService implements Startable {
         // make stream abortable
         const source = abortableDuplex(stream, timeoutController.signal)
 
-        await pipe(
+        await source.sink(pipe(
           [Identify.encode({
             listenAddrs,
             signedPeerRecord,
             protocols
           })],
-          lp.encode(),
-          source,
-          drain
-        )
+          lp.encode()
+        ))
       } catch (err: any) {
         // Just log errors
         log.error('could not push identify update to peer', err)
@@ -430,12 +427,8 @@ export class IdentifyService implements Startable {
       // make stream abortable
       const source = abortableDuplex(stream, timeoutController.signal)
 
-      await pipe(
-        [message],
-        lp.encode(),
-        source,
-        drain
-      )
+      const msgWithLenPrefix = pipe([message], lp.encode())
+      await source.sink(msgWithLenPrefix)
     } catch (err: any) {
       log.error('could not respond to identify request', err)
     } finally {