RequestBodySize.swift

public final class HTTPRequestBodySizeVerifyer: ChannelDuplexHandler, RemovableChannelHandler {
    public let maxSize: Int
    private var currentSize: Int
  
    public init(maxSize: Int) {
        self.maxSize = maxSize
        self.currentSize = 0
    }

    public func channelRead(context: ChannelHandlerContext, data: NIOAny) {
        let request = self.unwrapInboundIn(data)

        switch request {
        case .head, .end:
            self.currentSize = 0
            context.fireChannelRead(data)
        case .body(var part):
            self.currentSize += part.readableBytes
            guard self.currentSize > self.maxSize else {
                context.fireErrorCaught(Abort(.payloadTooLarge))  
            }
          
             context.fireChannelRead(data)
        }
    }
}