Simplify iobufpool usage

internal/iobufpool/iobufpool.go

@@ -37,9 +37,7 @@ func getPoolIdx(size int) int {
 
 // Put returns buf to the pool.
 func Put(buf []byte) {
-	buf = buf[:cap(buf)]
-
-	i := putPoolIdx(len(buf))
+	i := putPoolIdx(cap(buf))
 	if i < 0 {
 		return
 	}

internal/nbconn/bufferqueue.go

@@ -2,8 +2,6 @@ package nbconn
 
 import (
 	"sync"
-
-	"github.com/jackc/pgx/v5/internal/iobufpool"
 )
 
 const minBufferQueueLen = 8
@@ -70,7 +68,3 @@ func (bq *bufferQueue) growQueue() {
 	copy(newQueue, bq.queue)
 	bq.queue = newQueue
 }
-
-func releaseBuf(buf []byte) {
-	iobufpool.Put(buf[:cap(buf)])
-}

internal/nbconn/nbconn.go

@@ -114,7 +114,7 @@ func (c *NetConn) Read(b []byte) (n int, err error) {
 			buf = buf[copiedN:]
 			c.readQueue.pushFront(buf)
 		} else {
-			releaseBuf(buf)
+			iobufpool.Put(buf)
 		}
 		n += copiedN
 	}
@@ -292,7 +292,7 @@ func (c *NetConn) flush() error {
 
 			}
 		}
-		releaseBuf(buf)
+		iobufpool.Put(buf)
 	}
 
 	return nil