This function is actually called readFrom(int fd, int max_bytes)(PECL event >= 1.6.0)
EventBuffer::read — Read data from an evbuffer and drain the bytes read
   Read the first
   max_bytes
   from the buffer and drain the bytes read. If more
   max_bytes
   are requested than are available in the buffer, it only extracts as many
   bytes as available.
  
max_bytes
    Maxmimum number of bytes to read from the buffer.
   Returns string read, or false on failure.
  
| 版本 | 说明 | 
|---|---|
| PECL event 1.6.0 | Renamed EventBuffer::read()(the old method
        name) to EventBuffer::read().
        EventBuffer::read() now takes only max_bytesargument; returns string instead of
        integer. | 
This function is actually called readFrom(int fd, int max_bytes)