Revert "Only decompress Websocket frames that have the RSV1 bit set"

This reverts commit 636328c2.

src/vs/base/parts/ipc/node/ipc.net.ts

@@ -181,7 +181,6 @@ export class WebSocketNodeSocket extends Disposable implements ISocket {
 		state: ReadState.PeekHeader,
 		readLen: Constants.MinHeaderByteSize,
 		fin: 0,
-		rsv1Bit: 0,
 		mask: 0
 	};
 
@@ -397,7 +396,6 @@ export class WebSocketNodeSocket extends Disposable implements ISocket {
 				const peekHeader = this._incomingData.peek(this._state.readLen);
 				const firstByte = peekHeader.readUInt8(0);
 				const finBit = (firstByte & 0b10000000) >>> 7;
-				const rsv1Bit = (firstByte & 0b01000000) >>> 6;
 				const secondByte = peekHeader.readUInt8(1);
 				const hasMask = (secondByte & 0b10000000) >>> 7;
 				const len = (secondByte & 0b01111111);
@@ -405,7 +403,6 @@ export class WebSocketNodeSocket extends Disposable implements ISocket {
 				this._state.state = ReadState.ReadHeader;
 				this._state.readLen = Constants.MinHeaderByteSize + (hasMask ? 4 : 0) + (len === 126 ? 2 : 0) + (len === 127 ? 8 : 0);
 				this._state.fin = finBit;
-				this._state.rsv1Bit = rsv1Bit;
 				this._state.mask = 0;
 
 			} else if (this._state.state === ReadState.ReadHeader) {
@@ -458,12 +455,7 @@ export class WebSocketNodeSocket extends Disposable implements ISocket {
 				this._state.readLen = Constants.MinHeaderByteSize;
 				this._state.mask = 0;
 
-				if (this._zlibInflate && this._state.rsv1Bit) {
-					// See https://datatracker.ietf.org/doc/html/rfc7692#section-9.2
-					// Even if permessageDeflate is negotiated, it is possible
-					// that the other side might decide to send uncompressed frames
-					// So only decompress frames that have the RSV 1 bit set
-					//
+				if (this._zlibInflate) {
 					// See https://tools.ietf.org/html/rfc7692#section-7.2.2
 					if (this._recordInflateBytes) {
 						this._recordedInflateBytes.push(Buffer.from(<Buffer>body.buffer));