multi: add buffer.Write and pool.WriteBuffer, make GCQueue generic

buffer/utils.go

@@ -0,0 +1,17 @@
+package buffer
+
+// RecycleSlice zeroes byte slice, making it fresh for another use.
+// Zeroing the buffer using a logarithmic number of calls to the optimized copy
+// method.  Benchmarking shows this to be ~30 times faster than a for loop that
+// sets each index to 0 for ~65KB buffers use for wire messages. Inspired by:
+// https://stackoverflow.com/questions/30614165/is-there-analog-of-memset-in-go
+func RecycleSlice(b []byte) {
+	if len(b) == 0 {
+		return
+	}
+
+	b[0] = 0
+	for i := 1; i < len(b); i *= 2 {
+		copy(b[i:], b[:i])
+	}
+}