Imports of package tunnel

PathSynopsis
encoding/binaryPackage binary implements simple translation between numbers and byte sequences and encoding and decoding of varints.
encoding/jsonPackage json implements encoding and decoding of JSON as defined in RFC 7159.
github.com/pkg/errorsPackage errors provides simple error handling primitives.
ioPackage io provides basic interfaces to I/O primitives.
netPackage net provides a portable interface for network I/O, including TCP/IP, UDP, domain name resolution, and Unix domain sockets.