Buffer wraps zaptest.Buffer and provides convenience method JSONLine(n)
NewLogger creates a new zap.Logger backed by a zaptest.Buffer, which is also returned.
JSONLine reads n-th line from the buffer and converts it to JSON.
Lines overwrites zaptest.Buffer.Lines() to make it thread safe
String overwrites zaptest.Buffer.String() to make it thread safe
Stripped overwrites zaptest.Buffer.Stripped() to make it thread safe