Release 1.5.0

Performance

• BDP estimation and window update. (#1310)
• Do not flush NewStream header on client side for unary RPCs and streaming RPCs with requests. (#1343)
• Change objects in recvBuffer queue from interface to concrete type to reduce allocs (#1029)
• Don't create new reader in recvMsg (#940)

API change

• Add support for grpc.SupportPackageIsVersion3 back (#1331)
• Add Severity and VerboseLevel to grpclog. (#922)

Behavior change

• Transport errors should be coded Unavailable instead of internal. (#1307)
• Catch invalid use of Server.RegisterService after Register.Serve (#828)

Bug fixes

• Fix deadlock of roundrobin balancer (#1353)
• Use log severity and verbosity level (#1340)
• Protect bytesSent and bytesReceived with mutex to avoid datarace (#1318)
• Support IPv6 addresses in grpclb (#1303)
• Return header in Stream.Header() if available (#1281)
• Fix error handling on Stream deletion (#1275)

Documentation

• Add documentation to deprecate WithTimeout dial option (#1333)
• Specify characters allowed in metadata keys (#1299)
• Update LICENSE to Apache 2 (#1290)
• Update the path of guide (#950)

Testing

• latency: sleep in Write when BDP is exceeded to avoid buffer bloat (#1330)
• Replace 127.0.0.1 with localhost for ipv6 only environment (#1306)
• Create latency package for realistically simulating network latency (#1286)
• Use subtests for the benchmark_test and add it into the Makefile (#1278)