Panic on session.Close()

[cquon]

Seeing a panic on version v6.1.0 on session.Close(). When switching to v6.0.0 am not seeing this panic. Intuition is it is related to the connection pool changes.

Here's stack trace

2020-03-12T08:38:39.832442978Z panic: runtime error: invalid memory address or nil pointer dereference
2020-03-12T08:38:39.832487081Z [signal SIGSEGV: segmentation violation code=0x1 addr=0x60 pc=0xac4635]
2020-03-12T08:38:39.832505082Z 
2020-03-12T08:38:39.832520183Z goroutine 122 [running]:
2020-03-12T08:38:39.832541584Z sync.(*Mutex).Lock(...)
2020-03-12T08:38:39.832547184Z 	/usr/local/go/src/sync/mutex.go:74
2020-03-12T08:38:39.832553185Z .../vendor/gopkg.in/rethinkdb/rethinkdb-go%2ev6.(*Connection).Close(0x0, 0x0, 0x0)
2020-03-12T08:38:39.832582787Z 	.../vendor/gopkg.in/rethinkdb/rethinkdb-go.v6/connection.go:142 +0x35
2020-03-12T08:38:39.832589587Z .../vendor/gopkg.in/rethinkdb/rethinkdb-go%2ev6.(*Pool).Close(0xc000b14140, 0x0, 0x0)
2020-03-12T08:38:39.832595287Z 	.../vendor/gopkg.in/rethinkdb/rethinkdb-go.v6/pool.go:89 +0xe3
2020-03-12T08:38:39.832600888Z .../vendor/gopkg.in/rethinkdb/rethinkdb-go%2ev6.(*Node).Close(0xc00104ebd0, 0x0, 0x0, 0x0, 0x0, 0x0)
2020-03-12T08:38:39.832625989Z 	/.../vendor/gopkg.in/rethinkdb/rethinkdb-go.v6/node.go:59 +0x115
2020-03-12T08:38:39.832632090Z .../vendor/gopkg.in/rethinkdb/rethinkdb-go%2ev6.(*Cluster).Close(0xc000ef81e0, 0x0, 0x0, 0x0, 0x1b, 0xc000815fd8)
2020-03-12T08:38:39.832646791Z 	.../vendor/gopkg.in/rethinkdb/rethinkdb-go.v6/cluster.go:156 +0x99
2020-03-12T08:38:39.832668792Z .../vendor/gopkg.in/rethinkdb/rethinkdb-go%2ev6.(*Session).Close(0xc000abe0a0, 0x0, 0x0, 0x0, 0x0, 0x0)
2020-03-12T08:38:39.832701094Z 	.../vendor/gopkg.in/rethinkdb/rethinkdb-go.v6/session.go:227 +0x10d